I read this material in a local book which gives too little information so I need help to confirm.
The book said that we can use と to compare, and we cannot omit the last と.
いちご と すいかと、どちらがいいですか
Between strawberry and watermelon, which one do you like?
I cannot find confirmation if I could use it to compare more than two things. As in:
いちごとすいかとみかんと、どれがいいですか
And as it seems to be the same exhaustive と, can we really not omit the last と when it's used like this? If so, why is that?
This usage appears to be variant of "exhaustive と". We build an exhaustive list, which then behaves as any other plural noun would, and from which we then prompt for a choice. (Also, looking through GOO's and A Dictionary of Basic Japanese Grammar, it doesn't appear that any other と usage fits this example).
If we assume that it is indeed an exhaustive と usage, (and that no special exceptions are occurring), then listing more than two items or dropping/replacing the last と should both be okay.
Various example sentences suggest that no special exceptions are occurring here and that we can safely use "exhaustive と"s full range. For example, chocolate posted:
いちごとすいかとみかんのどれがいいですか？
Here we have a 3-item と list where the final と was replaced with the overall marker の. The rest of the sentence no longer "cares" about と and just sees a plural noun: LISTのどれがいいですか
On a final note, dropping a と in an exhaustive と list might have been less grammatical in the past. For example, see the third major entry (black-boxed-3) of the following link (note: is in Japanese), which says roughly that despite older usage rules, in modern usage it is acceptable to abbreviate the final と. (From this we might reasonably infer that explicitly adding every と might make a sentence sound more formal or old-fashioned):
http://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/
For reference According to the "exhaustive と" entry in Tae Kim's Guide to Japanese Grammar (http://www.guidetojapanese.org/learn/grammar/nounparticles), you can definitely list more than two nouns in an exhaustive list joined with と, and the last noun usually takes a different particle marking the list's overall function.
So for example:
ピザとスイカとイチゴを食べました。
is grammatical.
[Edit: removed discussion of と vs か, was not relevant]
