You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: A circular swimming pool is surrounded by a concrete wall 4 feet wide.if the area of the wall is 11/25 of the area of the pool, then the radius of the pool in feet is?

 Option A: 22

 Option B: 20

 Option C: 9

 Option D: 8

 Option E: 1
Option B

Question: The time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream. If the speed of the boat in still water is 42 kmph, find the speed of the stream?

 Option A: 12

 Option B: 15

 Option C: 14

 Option D: 18

 Option E: 19
Option C

Question: a right triangle has three sides (F, G, H). If F=5, G=8.66, and H=10, which angle is 90 degrees

 Option A: FG

 Option B: HG

 Option C: HF

 Option D: n/a

 Option E: n/a

Option A