Comparing Three or More Items

To compare three or more items and create a sort of "most" statement (i.e., "Of these, which is the most X"), there's a standard sentence format used. This is from Genki.

[Class of items] の中で　A がいちばん [property].
Among [class of items], A is the most [property] .

ロシアとフランスと日本の中で、どこがいちばん寒いですか。
Between Russia, France, and Japan, which country has the coldest climate?

ロシアがいちばん寒いです。
Russia is the coldest.

This is a pretty simple pattern to follow since it more closely mimics the word order in English. One thing to note is the question word that's used. In the above example it's どこ, because it's referencing a group of locations. Other standard question words can be used here too, though.

季節の中でいつがいちばん好きですか。
Which season do you like the most?

秋がいちばん好きです。
I like fall the most.

In this case,  I believe いつ is used because it's referring to a certain time of year, making it a "when" question. Also, saying いちばん好き is a common way to mark something as "favorite" or "the one I like the most."

Picking a question word when it comes to discussing actual items is a bit easier. It's common to use どれ when an explicit list of items is given, and 何 when a collective group is given. Again, from Genki.

りんごとみかんとさくらんぼの中で、どれがいちばん好きですか。
Between apples, tangerines, and cherries, which one do you like the most?

果物の中で何がいちばん好きですか。
What fruit do you like the most?

This makes sense to me because どれ is used as "which", so it sounds more appropriate when choosing from a list. And with 何 used as "what", having to pick from a group sounds right.