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: 3 ltr of water is added with 9 ltr of a solution containing 57 % of alcohol in the water. the % of alcohol in the new mixture is ?
Options: a. 41.5 %, b. 42.75 %, c. 43 %, d. 45 %, e. 45.75 %
[A]: b


[Q]: Problem: what is the tens digit of 6 ^ 10 ?
Options: a. 7, b. 3, c. 5, d. 1, e. 9
[A]: a


[Q]: Problem: stacy has a 63 page history paper due in 7 days. how many pages per day would she have to write to finish on time ?
Options: a. 9, b. 8, c. 10, d. 8.5, e. 6
[A]:
a