Detailed Instructions: You are given a mathematical question described with an open-ended vocabulary. Questions in this task involve real-world situations, describing a mathematical problem. You are also given 4 or 5 answer options (associated with "A", "B", "C", "D", "E"). Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. LaTeX mathematical format (the standard way to express mathematical expressions in the typesetting software known as LaTeX) is used to express equations. Each question is solvable with high school math knowledge. Give only one answer for each question.
See one example below:
Problem: John has y dollars to spend on some new CDs from Music Plus, an online record store. He can buy any CDs at the members' price of x dollars each. To be a member, John has to pay a one-time fee of $19. Which of the following expressions represents the number of CDs John can purchase from Music Plus?
(A)\(\frac{xy}{19}\) (B)\(\frac{y + 19}{x}\) (C)\(\frac{2y - x}{19}\) (D)\(\frac{y - 19}{x}\) (E)\(\frac{19 - x}{y}\)
Solution: D
Explanation: john must pay 19 dollar to buy a membership then he will have \(y-19\) dollar remaining so he can buy \(rac{y - 19}{x}\) CDs.

Problem: A survey of all the students who attend Central Valley High School showed that there was an average (arithmetic mean) of 33.6 students per class room and and average of 22.4 electronic devices brought to class by students per classroom. If 4,200 students attend Central Valley High School, which of the following is the best estimate of the total number of electronic devices in the classrooms of Central Valley?
(A)1,680 (B)2,520 (C)2,800 (D)4,075 (E)6,300
Solution:
C