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: what number must be added to 6, 16 and 8 to get an average of 13 ?
Options: a. 23, b. 22, c. 44, d. 33, e. 55

A: b
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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
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Q: Problem: the average salary / head of all the workers in a workshop is rs. 1100, if the average salary / head of 9 technician is rs. 1300 and the average salary / head of the rest is rs. 880, the total no. of workers in the work - shop is ?
Options: a. 18, b. 20, c. 22, d. 17, e. 26

A:
d
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