Detailed Instructions: 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.
Q: Problem: a sum was put at simple interest at a certain rate for 10 years. had it been put at 5 % higher rate, it would have fetched rs. 600 more. what was the sum ?
Options: a. rs. 1200, b. rs. 1300, c. rs. 1400, d. rs. 1500, e. none of these
A:
a