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: a person borrows 20000 for 6 years at 8 % p. a. simple interest. he immediately lends it to another person at 9 % p. a. for 6 years. find his gain in the transaction per year.
Options: a. 200, b. 250, c. 210, d. 190, e. 180
A:
a