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: if the length and breadth of a rectangular room are each increased by 1 m, then the area of floor is increased by 21 sq. m. if the length is creased by 1 m and breadth is decreased by 1 m, then the area is decreased by 5 sq. m. the perimeter of the floor is :
Options: ['a. 27', 'b. 35', 'c. 40', 'd. 49', 'e. 38']
A:
c