Identify the choice that correctly completes the sentence: of these paintings were damaged by the flood.

For this question, the choices are:
1) Each
2) Both
3) Either
4) Neither

And the answer is both because it is the only plural pronoun that refers to one or more nouns in the sentence, hence the use of "were". Each, either and neither refer to only one of the other and thus would use "was" instead of "were" to refer to a singular noun.