The efficiency of a solar panel is determined by the quality of its silicon ___________ monocrystalline, polycrystalline, and thin-film.

6
writing

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

A

cells,

B

cells;

C

cells; which are

D

cells:

Correct Answer: D

Choice D is the best answer. A colon is used to introduce the list of silicon cell types.

Choice A is incorrect because a comma is too weak. Choice B is incorrect because a semicolon separates independent clauses. Choice C is incorrect because "which are" makes the list a dependent clause, making the semicolon incorrect.