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: when positive integer n is divided by 7, the remainder is 1. when n is divided by 11, the remainder is 5. what is the smallest positive integer k such that k + n is a multiple of 77 ?
Options: a. 2, b. 4, c. 6, d. 8, e. 10
[EX A]: c

[EX Q]: Problem: a bag of potatoes weighs 60 lbs divided by half of its weight. how much does the bag of potatoes weight ?
Options: a. 20 lb, b. 11 lb, c. 10 lb, d. 15 lb, e. 5 lb
[EX A]: b

[EX Q]: Problem: a 90 cm long wire is to be cut into two pieces so that one piece will be 2 / 7 th of the other, how many centimeters will the shorter piece be ?
Options: a. a. 73, b. b. 20, c. c. 83, d. d. 21, e. e. 52
[EX A]:
b