Vertical farming, a method of growing crops in vertically stacked layers, often utilizes controlled-environment agriculture technology. By optimizing plant growth with ______ vertical farms can produce high yields without the need for pesticides or natural sunlight.
Which choice completes the text so that it conforms to the conventions of Standard English?
artificial lighting, provided by LEDs,
artificial lighting provided by LEDs
artificial lighting provided by LEDs,
artificial lighting, provided by LEDs
Correct Answer: C
Choice C is the best answer. The sentence begins with the prepositional phrase "By optimizing plant growth with artificial lighting provided by LEDs," which serves as an introduction to the main clause. A comma is required after "LEDs" to separate this long introductory phrase from the main subject "vertical farms."