选A either 任何一个 ；这道题考词汇意思和用法：both 两者；all 全部；还因为其谓语是单数,所以选either
Here are two apples.Which one would you like?
这里有两个苹果.你想要哪一个?
Either is OK.I don't mind.
任何一个都可以.我无所谓.