1. Don't worry about where the endowment and other temple ordinances came from. There is no need to rock the boat so there is no reason to investigate where the temple ceremonies were possibly derived from. Reliance upon the word and actions of those members that have gone through the temple before is good enough.
(This is probably the most commonly selected option although it shouldn't be if the member also believes in D&C 93:36 which states that "The glory of God is intelligence".)
2. The temple ordinances are the same as those practiced thousands of years ago. The reason for the similarities to the Masonic rites is that the Masons carried on a practice that gradually became corrupted which Joseph Smith restored as the 'true endowment' after learning about Masonry.
(This option was widely accepted by early church leaders such as Heber C. Kimball who said, "...there is a similarity of preasthood in Masonry. Bro. Joseph says Masonry was taken from preasthood but has become degen[e]rated. but menny things are perfect." (spelling from the original) Kimball also said, "The Masonry of today (1840s) is received from the apostasy which took place in the days of Solomon and David. They have now and then a thing that is correct, but we have the real thing". Many others also take this option such as Hugh Nibley and some Mormons who are also Masons. For some of the problems with this belief, see this site, this site, and brush up on your history of when the 5 points of fellowship were introduced into Masonry and why they were removed from the revised 1990 endowment. If this option is the one selected, an adequate explanation as to why the restored-through-Joseph-Smith-'true' endowment which more closely resembles early 19th century Masonry (rather than earlier forms of Masonry) has since been modified to make the similarities less obvious and smaller in number. See David Stevenson's The Origins of Freemasonry: Scotland's Century, 1590-1710 for details on the evolution of pre-Mormon era Masonry and the 5 points--of which only two of the five remained unmodified during the 100+ years before Morgan's book.)
3. There is no connection between Masonry and the LDS temple ordinances. Joseph Smith divinely received what he needed to know in order to create the temple ordinances. The early Mormon involvement with Masonry is either a lie (which need not be investigated) or the parallels between Mormonism and Masonry are "superficial", "few", and/or "coincidental".
(This is the position taken by many who either fail to research the issue or who would rather not admit that the similarities to the original endowment are very significant. This includes FARMS and Jeff Lindsay who states that the similarities to Masonry are both superficial AND indicative of ancient rituals carried down by the Masons. These contradictory views would seemingly be difficult to argue, but Jeff does before coming to the conclusion that "...[I] reject the allegation that the Temple was derived from Masonry".)
4. We should not be concerned with matters of the intellect. A reliance on faith is where I place my trust. Although I know intellectually where the endowment came from, I choose to ignore the facts and place my trust in God, the current prophet, and Joseph Smith.
(The reasoning is once again faulty based on the scripture noted in option #1.)
5. (this option came in from a site visitor) Although I know intellectually where the endowment came from, it seems to me that what is important about it is the way it affects the participant. If people find it to be a worshipful experience, and if it affirms values that are important to the participant, then its origins don't really matter. What matters is that it symbolizes and sacralizes important beliefs and behaviors such as family ties, fidelity, honesty, faith, and commitment to the community of faith and to the greater good of that community.
(Few in the church probably fall into this category although the number may be growing. This is basically a post-modernist view. It is a growing way of dealing not only with the the temple, but also with other Mormon truth claims and scriptures.)
(an addendum to this option came in from another site visitor as follows:) I can add a corrolary to number five - and a defense of that position. Many christians including myself, practice and participate in many, many, pagan rituals--Christmas Trees, yule logs, Halloween traditions, the Easter Bunny, and the Tooth Fairy. I choose to do so for the benefit to my family and the positive impact on my kids. I choose to disregard the documented and certified pagan roots. However, I do not claim any of them to be doctrine or God inspired. They are in no way part of my theological platform of faith. So, I guess you can add a 5b - participate, don't investigate or validate, enjoy but don't ascribe theology to anything so trite or ritualistic and so suspiciously connected to Masonry.
a response from the author of the original option #5
7. Whoever in the Middle Ages developed the rituals that Smith "borrowed" was inspired. Mormons generally believe that Christopher Columbus, Martin Luther, and George Washington were inspired to lay parts of the foundation for the restored gospel in 1830. Perhaps in the same way the evolution of Masonry was being guided by Providence to prepare for the endowment. Some reasons why this might have been necessary or desirable would be 1) to serve as "hints" from God to Joseph as to what the endowment should contain. 2) It allowed Smith to have people to give the ritual to who wouldn't be alienated by this type of ceremony. 3) It created a background in society against which the true meaning and significance of the endowment could be camouflaged.