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 sum of all 3 digit numbers that leave a remainder of ' 2 ' when divided by 7 ?
Options: a. 70,592, b. 64,850, c. 64,749, d. 149,700, e. 156,720
[EX A]: a

[EX Q]: Problem: in 10 years, a will be twice as old as b was 10 years ago. if a is now 5 years older than b the present age of b is
Options: a. 37, b. 38, c. 39, d. 35, e. 41
[EX A]: d

[EX Q]: Problem: a man has some hens and cows. if the number of heads be 100 and the number of feet equals 240, then the number of cows will be :
Options: a. 22, b. 23, c. 24, d. 20, e. 28
[EX A]:
d