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.
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Question: 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

Answer: a


Question: Problem: how many multiples of 4 are there between 12 and 104, inclusive ?
Options: a. 21, b. 22, c. 23, d. 24, e. 25

Answer: d


Question: Problem: last year sandy saved 10 % of her annual salary. this year, she made 10 % more money than last year, and she saved 6 % of her salary. the amount saved this year was what percent of the amount she saved last year ?
Options: a. 66 %, b. 80 %, c. 112 %, d. 136 %, e. 148 %

Answer:
a