Which choice completes the text so that it conforms to the conventions of Standard English?
A
is,
B
are,
C
have been,
D
were,
Explanation
Correct answer: A.
Choice A is the best answer. The convention being tested is subject-verb agreement. The singular verb "is" agrees in number with the singular subject "the Proto-Nilotic language."
Why the other choices are wrong
Choice B
Choice B is incorrect because the plural verb "are" doesn’t agree in number with the singular subject "the Proto-Nilotic language."
Choice C
Choice C is incorrect because the plural verb "have been" doesn’t agree in number with the singular subject "the Proto-Nilotic language."
Choice D
Choice D is incorrect because the plural verb "were" doesn’t agree in number with the singular subject "the Proto-Nilotic language."