Which sentence shows correct subject-verb agreement with a plural subject at the start of a sentence?

Which sentence shows correct subject-verb agreement with a plural subject at the start of a sentence?

• A. Ten dollars were enough to buy a book.
• B. Ten dollars are enough to buy a book.
• C. Ten dollars is enough to buy a book.
• D. Ten dollars be enough to buy a book.

Answer: (C)

The main idea here is how verb form agrees with a quantity when the subject is a numerical amount. When a phrase like ten dollars refers to a total sum, English treats that amount as a single unit, so the verb should be singular. Ten dollars is enough to buy a book conveys that one total amount suffices. Using are would treat the dollars as separate items rather than one combined amount, which isn’t the intended sense here. Ten dollars be enough isn’t a standard or correct present-tense construction. So the sentence with the singular verb is the correct choice.