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 waitress ' s income consists of her salary and tips. during one week, her tips were 3 / 4 of her salary. what fraction of her income for the week came from tips ?
Options: a. 1 / 9, b. 1 / 6, c. 3 / 7, d. 4 / 9, e. 5 / 9

Output: c


Input: Consider Input: Problem: in a room filled with 6 people, all 6 people have exactly 1 sibling in the room. if two individuals are selected from the room at random, what is the probability that those two individuals are not siblings ?
Options: a. 3 / 5, b. 4 / 5, c. 5 / 6, d. 5 / 12, e. 7 / 12

Output: b


Input: Consider Input: Problem: the sub - duplicate ratio of 25: 49 is
Options: a. 4: 3, b. 5: 7, c. 6: 4, d. 1: 4, e. 2: 3


Output: b