Question mathem

3.2 Form, Structure, and Sense - Modifier placement and clarity
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Mathematician Grigori Perelman, sometimes in conjunction with mathematicians Richard S. Hamilton and Shing-Tung Yau, blank credited with proving the Poincaré conjecture. Having built on Hamilton’s previous work to solve the proof, Perelman has insisted that Hamilton receive credit. Yau later found and closed gaps in Perelman’s proof, persuading some mathematicians that he deserves credit as well.

Which choice completes the text so that it conforms to the conventions of Standard English?

A.

are

B.

have been

C.

are being

D.

is

Mathematician Grigori Perelman, sometimes in conjunction with mathematicians Richard S. Hamilton and Shing-Tung Yau,

Hard-difficulty · SAT Reading & Writing · Form, Structure, and Sense — Modifier placement and clarity. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice D is the best answer. The convention being tested is subject-verb agreement. The singular verb "is credited" agrees in number with the singular subject "mathematician Grigori Perelman."

Choice A is incorrect because the plural verb "are credited" doesn’t agree in number with the singular subject "mathematician Grigori Perelman." Choice B is incorrect because the plural verb "have been credited" doesn’t agree in number with the singular subject "mathematician Grigori Perelman." Choice C is incorrect because the plural verb "are being credited" doesn’t agree in number with the singular subject "mathematician Grigori Perelman."