These three ways are equally correct, even similarly constructed. Like synonyms, you can basically think of them collectively as one expression. Speaking of construction, the three examples given are all asking if "you prefer an object". There's another way of construction, "are you [a person who prefers this object]". For instance: 1) 你是甜党还是咸党？Do you like it sweet or savory? = 你比较喜欢甜豆腐脑还是咸豆腐脑？ （xx党 means zealots for something, very informal) 2) 你是早起鸟还是夜猫子？ Do you prefer working in the morning, or pull all-nighters? =你更喜欢早起还是晚睡？ （lit. early bird vs. night owl) In these cases, you are still asking about one's preferences, by asking if s/he/them has a certain attribute. In this construct, the attributes are often contrasting. With this construct you can work in your nuances by doing some word play. For example: 3) 你是领导还是领导者？ Would you want to simply have the position to boss people around, or lead them with your wisdom and charisma? (similar trick exists in English, "would you rather be the butcher or the butchered") I must add, your examples' constructs are more common and straight-forward.

Douglas.EN, Darker & maxine: Thank you!

I would say A coz more normally

All three are correct translations for the "do you prefer A or B" thing. But usually we just say "do you like A or B", hence 你喜欢（or 想喝）葡萄酒还是啤酒？

A\B\C are all correct. Chinese can get your point, take it easy. a\b\c都是对的，中国人都能明白你想问什么？放轻松