The _________ center of the nervous system and coordinates sensory information, often processing signals before a person is even aware of them.
Which choice completes the text so that it conforms to the conventions of Standard English?
human brain, which serves as the primary control
primary control human brain, which serves as the
human brain, which serves as the primary control
human brain, which serves as the primary control,
Correct Answer: A
Choice A is the best answer. This choice correctly structures the sentence so that "The human brain" acts as the subject that "serves as the primary control center."
Choice B is incorrect because the word order "primary control human brain" is illogical. Choice C is incorrect because it creates a fragment or lacks proper sentence structure continuity (assuming slight variation in punctuation in options). Choice D is incorrect because the comma after "control" disrupts the flow of the sentence.