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.

Flour, sugar, and baking soda are mixed by weight in the ratio of 6:4:2, respectively, to produce a certain type of cookie. In order to make 6 pounds of this dough, what weight of sugar, in pounds, is required?
(A)4 (B)2 (C)\(\frac{7}{6}\) (D)\(\frac{1}{2}\) (E)\(\frac{1}{4}\)
B

A new airplane can travel at speeds up to 4,680 miles per hour. Assuming that the airplane is traveling at top speed, how many miles can it travel in 10 seconds?
(A)1.3 (B)7.8 (C)13 (D)78 (E)130
C

After 21 students were added to a class, there were four times as many students as before. How many students were in the class before the addition?
(A)3 (B)7 (C)11 (D)14 (E)17

B