
Catherine M. answered 04/30/19
Ph.D. Professor and Language Instructor
The relationship between the two halves of the sentence is one of contrast, so the joining conjunction must be one that establishes contrast.
"AND" establishes commonality, so choice (A-no change) cannot work. (C) demonstrates contrast, but the wording is "wordy." Choice D is wordy, so in this case, (B) would be the best choice.