Task: Question Answering
Input (English): Question: There are two water tanks A and B, A is much smaller than B. While water fills at the rate of one liter every hour in A, it gets filled up like 10, 20, 40, 80, 160 in tank B. (At the end of first hour, B has 10 liters, second hour it has 20, third hour it has 40 and so on). If tank B is 1/32 filled after 21 hours, what is the total duration required to fill it completely?

 Option A: 22

 Option B: 28

 Option C: 269

 Option D: 26

 Option E: 82
Output (English): Option D