Task: Question Answering
Input (English): Problem: a certain sum is invested at simple interest at 18 % p. a. for two years instead of investing at 12 % p. a. for the same time period. therefore the interest received is more by rs. 480. find the sum ?
Options: a. 7000, b. 7029, c. 4000, d. 2800, e. 2791
Output (English): c