You will be given a definition of a task first, then some input of the task.
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 how many years rs 100 will produce the same interest at 5 % as rs. 200 produce in 2 years at 10 %
Options: a. 8, b. 10, c. 9, d. 12, e. 11
Output:
a