The company's _________ "smart glass," five years in development, allows windows to tint automatically.

6
writing

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

A

product

B

product-

C

product,

D

product:

Correct Answer: C

Choice C is the best answer. A comma is used to set off the appositive "smart glass" which follows "product."

Choice A is incorrect because punctuation is needed to set off the appositive. Choice B is incorrect because a dash should be paired with another dash if used for appositives. Choice D is incorrect because a colon is not standard here.