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