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.

[EX Q]: Problem: what is the compound interest paid on a sum of rs. 3000 for the period of 2 years at 10 % per annum.
Options: a. 630, b. 620, c. 610, d. 600, e. none of these
[EX A]: a

[EX Q]: Problem: he average of 10 numbers is 23. if each number is increased by 4, what will the new average be ?
Options: a. 26, b. 27, c. 88, d. 99, e. 12
[EX A]: b

[EX Q]: Problem: find large number from below question the difference of two numbers is 1000. on dividing the larger number by the smaller, we get 10 as quotient and the 10 as remainder
Options: a. 1234, b. 1110, c. 1456, d. 1200, e. 1600
[EX A]:
b