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.

Problem: at a certain university, 65 % of the professors are women, and 70 % of the professors are tenured. if 90 % of the professors are women, tenured, or both, then what percent of the men are tenured ?
Options: a. 25, b. 37.5, c. 50, d. 62.5, e. 75
d

Problem: if y exceeds x by 25 %, then x is less than y by ?
Options: a. 28 %, b. 21 %, c. 20 %, d. 30 %, e. 29 %
c

Problem: a and b are two partially filled buckets of water. if 5 liters are transferred from a to b, then a would contain one - third of the amount of water in b. alternatively, if 4 liters are transferred from b to a, b would contain one - half of the amount of water in a. bucket a contains how many liters of water ?
Options: a. 11, b. 52 / 5, c. 17, d. 21, e. 23

b