Concept:"Either" is used when making a choice between two options.
Explanation:The sentence refers to "these two books," so there are only two possible choices.
"Either" means one or the other of two items, not both.
Thus, "You can have either of these two books" means you may choose one book while excluding the other.
"Any" is not correct because it is used with three or more options.
"None" means not any of the two, which contradicts the positive meaning of "can have."
"Some" refers to an indefinite part of a group, not a clear alternative between two.
Therefore, the word that best completes the sentence is "either."
Answer:A. either