In the 1980s, a popular subgenre of rock music ______ called 'hair metal'—named for rockers' long, dramatic hairstyles.

• A. Was
• B. Were
• C. Is
• D. Are

Answer: (A)

The main idea here is subject-verb agreement with a past-time frame. The subject is singular: “a popular subgenre of rock music.” When the time reference is in the past, the verb should be in the past tense to match. That makes the natural fill-in the past tense singular form: “was.” The rest of the clause—“called 'hair metal'—named for rockers' long, dramatic hairstyles”—provides a descriptive title and explanation and doesn’t require a different number or tense. Using “were” would treat the subject as plural, and “is” or “are” would shift to present tense, which clashes with the time phrase “In the 1980s.”