31.
Your Answer is
Correct Answer is A
Explanation
During guides the adverbial of time, separated from the main clause by a comma, and the subject of the sentence is engineers without the conjunction and, so A is correct.
31.
Your Answer is
Correct Answer is A
Explanation
During guides the adverbial of time, separated from the main clause by a comma, and the subject of the sentence is engineers without the conjunction and, so A is correct.