Dear Friends,
Here is a detailed explanation to this question-
Raxit85
Learning about how best to use social media, particularly with such complex issues, are challenging, but the marketing department have committed to a firm deadline to resolve these issues by the end of this quarter.
A) are challenging, but the marketing department have
B) is challenging, but the marketing department has
C) are challenging, but the marketing department has
D) is challenging, but the marketing department have
E) are challenging, but the marketing department had
A: This answer choice features two instances of subject-verb disagreement; the plural verb "are" is used to refer to the singular verb phrase "Learning about how best to use social media", and the plural verb "have" is used to refer to the singular noun "marketing department". Thus, this answer choice is incorrect.
B: This answer choice maintains proper subject-verb agreement throughout the sentence. Thus, this answer choice is correct.
C: This answer choice repeats the subject-verb disagreement between "are" and "Learning...", seen in Option A. Thus, this answer choice is incorrect.
D: This answer choice repeats the subject-verb disagreement between "have" and "marketing department" seen in Option A. Thus, this answer choice is incorrect.
E: This answer choice repeats the subject-verb disagreement between "are" and "Learning...", seen in Option A. Thus, this answer choice is incorrect.
Hence, B is the best answer choice.The confusion, in this question, regarding the subject-verb agreement, stems from two sources. First, the confusion regarding the use of "are" stems from the fact that the verb is right next to the plural noun "issues". However, as the phrase "particularly with such complex issues" is between two commas, it provides extra information and the clause "is/are challenging" modifies the verb phrase "Learning how to...". Secondly, the confusion regarding the use of "have" stems from the use of the collective noun "marketing department"; remember, although a collective noun is comprised of multiple individual constituents, it is treated as a singular noun.
To understand the concept of "Extra Information Between Two Commas on GMAT, you may want to watch the following video (~1 minute):
To understand the concept of "Collective, Countable, and Uncountable Nouns on GMAT" you may want to watch the following video (~2 minutes):
All the best!
Experts' Global Team