Millions of dollars ___ spent. A. are B. is And why ?

The correct answer is A. "are" This is because "millions of dollars" is considered a plural subject (it refers to more than one million), and therefore, it requires the plural form of the verb "to be", which is "are". In English, subject-verb agreement rules dictate that singular subjects require singular verbs, and plural subjects require plural verbs. In this case, "millions of dollars" is a plural subject, so it needs a plural verb, "are".