Teacher: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.
Teacher: Now, understand the problem? Solve this instance: Problem: the compound interest earned by sunil on a certain amount at the end of two years at the rate of 10 % p. a. was rs. 420. find the total amount that sunil got back at the end of two years in the form of principal plus interest earned.
Options: a. rs. 2530, b. rs. 2430, c. rs. 2420, d. rs. 2410, e. rs. 2440
Student:
c