Final answer:
The container was being filled with water for the entire 3 hours, so there was no time when it was not being filled. Hence the correct answer is option D
Step-by-step explanation:
The question is asking about the time during the 3 hours when the container was not actually being filled with water. To find this, we need to subtract the time the container was being filled from the total time of 3 hours. Since the container was being filled for the entire 3 hours, the answer is d) 0 hours.