Q: 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 22 m at the rate of rs. 2.50 a meter ?
Options: a. 188, b. 172, c. 278, d. 279, e. 222
A:
b