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.

Ex Input:
Problem: the diagonal of a rectangle is √ 41 cm and its area is 20 sq. cm. the perimeter of the rectangle must be :
Options: ['a. 18', 'b. 28', 'c. 38', 'd. 48', 'e. 58']

Ex Output:
a


Ex Input:
Problem: ray writes a two digit number. he sees that the number exceeds 4 times the sum of its digits by 3. if the number is increased by 18, the result is the same as the number formed by reversing the digits. find the number.
Options: a. 2, b. 5, c. 6, d. 7, e. 8

Ex Output:
b


Ex Input:
Problem: mr. loyd wants to fence his square shaped land of 120 sqft each side. if a pole is laid every 12 ft how many poles do he need ?
Options: a. 20, b. 30, c. 40, d. 50, e. 60

Ex Output:

c