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: when positive integer n is divided by 3, the remainder is 1. when n is divided by 7, the remainder is 5. what is the smallest positive integer k such that k + n is a multiple of 21 ?
Options: a. 2, b. 4, c. 6, d. 8, e. 10
[A]: a


[Q]: Problem: in a room filled with 6 people, all 6 people have exactly 1 sibling in the room. if two individuals are selected from the room at random, what is the probability that those two individuals are not siblings ?
Options: a. 3 / 5, b. 4 / 5, c. 5 / 6, d. 5 / 12, e. 7 / 12
[A]: b


[Q]: Problem: the average of 10 numbers is 7. if each number is multiplied by 12, then the average of new set of numbers is
Options: a. 28, b. 236, c. 288, d. 84, e. 26
[A]:
d