Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Problem: find the cost of fencing around a circular field of diameter 32 m at the rate of rs. 2 a meter ?
Options: a. 201, b. 132, c. 772, d. 592, e. 261
a

Problem: the cross - section of a cannel is a trapezium in shape. if the cannel is 12 m wide at the top and 2 m wide at the bottom and the area of cross - section is 4200 sq m, the depth of cannel is ?
Options: a. 500, b. 600, c. 700, d. 800, e. 900
b

Problem: set s consists of integers { 8, 11, 12, 14, 15 }. if integer n is included in the set, the average ( arithmetic mean ) of set s will increase by 25 %. what is the value of integer n ?
Options: a. 28, b. 32, c. 36, d. 40, e. 44

d