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: a man goes downstream at 10 kmph, and upstream 8 kmph. the speed of the stream is
Options: a. 0 kmph, b. 4 kmph, c. 1 kmph, d. 2.5 kmph, e. 26 kmph

Output: c


Input: Consider Input: Problem: 3 ltr of water is added with 9 ltr of a solution containing 57 % of alcohol in the water. the % of alcohol in the new mixture is ?
Options: a. 41.5 %, b. 42.75 %, c. 43 %, d. 45 %, e. 45.75 %

Output: b


Input: Consider Input: Problem: if 7 spiders make 7 webs in 7 days, then how many days are needed for 1 spider to make 1 web ?
Options: a. 1, b. 7, c. 3, d. 14, e. 16


Output: b