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: the dimensions of a room are 25 feet * 15 feet * 12 feet. what is the cost of white washing the four walls of the room at rs. 7 per square feet if there is one door of dimensions 6 feet * 3 feet and three windows of dimensions 4 feet * 3 feet each ?
Options: a. s. 4538, b. s. 6342, c. s. 4518, d. s. 4530, e. s. 4517
[A]: b

[Q]: Problem: a man can row upstream at 25 kmph and downstream at 55 kmph, and then find the speed of the man in still water ?
Options: a. 65, b. 40, c. 30, d. 78, e. 38
[A]: b

[Q]: Problem: in a recent election, geoff received 15 percent of the 6,000 votes cast. to win the election, a candidate needed to receive more than x % of the vote. if geoff needed exactly 3,571 more votes to win the election, what is the value of x ?
Options: a. 74.5, b. 54, c. 56, d. 60, e. 63
[A]:
a