Which choice completes the text so that it conforms to the conventions of Standard English?
A
vary
B
has varied
C
varies
D
is varying
Explanation
Correct answer: A.
Choice A is the best answer. The convention being tested is subject-verb agreement. The plural verb “vary” agrees in number with the plural subject “such phrases.” The supplementary phrase “known as story starters,” set off by commas, doesn’t change the subject’s number.
Why the other choices are wrong
Choice B
Choice B is incorrect. The singular verb phrase “has varied” doesn’t agree in number with the plural subject “such phrases.”
Choice C
Choice C is incorrect. The singular verb “varies” doesn’t agree in number with the plural subject “such phrases.”
Choice D
Choice D is incorrect. The singular verb phrase “is varying” doesn’t agree in number with the plural subject “such phrases.”