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: if julie rows 32 km upstream and 72 km down steam taking 4 hours each, then the speed of the stream
Options: a. 1.5 kmph, b. 0.5 kmph, c. 0.4 kmph, d. 1.6 kmph, e. 2.5 kmph

Output: b


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: kim finds a 6 - meter tree branch and marks it off in thirds and fifths. she then breaks the branch along all the markings and removes one piece of every distinct length. what fraction of the original branch remains ?
Options: a. 7 / 5, b. 1 / 2, c. 8 / 15, d. 2 / 5, e. 3 / 5


Output: e