Answer:
He had 5 minutes left for question C.
Explanation:
20 minutes to do the quiz.
He spent:
11 minutes on question A
4 minutes of question B.
So, for the first 2 questions, he used 15 minutes.
How much time did he have left for question C?
Total of 20 minutes, in the first two questions he used 15. So
20 - 15 = 5
He had 5 minutes left for question C.