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.

Input: Consider Input: Problem: an assembly line produces 15 cogs per hour until an initial order of 60 cogs is completed. the speed of the assembly line is then immediately increased so that it can produce 60 cogs per hour until another 60 cogs are produced. what is the overall average output, in cogs per hour, for the assembly line during this whole time ?
Options: a. 20, b. 22, c. 24, d. 26, e. 28

Output: c


Input: Consider Input: Problem: a 340 - liter solution of kola is made from 88 % water, 5 % concentrated kola and the rest is made from sugar. if 3.2 liters of sugar, 10 liter of water and 6.8 liters of concentrated kola were added to the solution, what percent of the solution is made from sugar ?
Options: a. 6 %., b. 7.5 %., c. 9.2 %., d. 10.5 %., e. 11 %.

Output: b


Input: Consider Input: Problem: the average age of a group of n people is 14 years old. one more person aged 32 joins the group and the new average is 16 years old. what is the value of n ?
Options: a. 5, b. 6, c. 7, d. 8, e. 9


Output: d