This question is testing the understanding of verb conjugation in English. The correct answer is 'B. Are' because 'they' is a plural pronoun and 'are' is the correct form of 'to be' that corresponds with plural pronouns. Option A is incorrect because 'is' is used with singular pronouns or singular nouns. Option C is incorrect because 'am' is used with the pronoun 'I'. Option D is incorrect because 'be' is the base form of the verb and not conjugated for any pronoun.