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: in may, the grounds keeper at spring lake golf club built a circular green with an area of 36 square feet. in august, he doubled the distance from the center of the green to the edge of the green. what is the total area of the renovated green ?
Options: ['a. 100 pi', 'b. 144 pi', 'c. 70', 'd. 80', 'e. 90']
A:
b