3D printing _______ allows engineers to create complex prototypes quickly without the need for expensive molds.
Which choice completes the text so that it conforms to the conventions of Standard English?
technology. which utilizes additive manufacturing,
technology-which utilizes additive manufacturing
technology which utilizes additive manufacturing
technology, which utilizes additive manufacturing,
Correct Answer: D
Choice D is the best answer. The clause "which utilizes additive manufacturing" is a nonrestrictive relative clause (it adds extra info about 3D printing but isn't essential to identify it). It requires commas on both sides.
Choice A is incorrect because the period creates a fragment. Choice B is incorrect because it uses a dash without a closing dash. Choice C is incorrect because "which" clauses are typically nonrestrictive and require commas.