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: subtracting 3 % of a from a is equivalent to multiplying a by how much ?
Options: a. 0.97, b. 9.4, c. 0.094, d. 94, e. none
a

Problem: what is the units digit of 32 ! + 50 ! + 4 ! + 4 ! ?
Options: a. 0, b. 2, c. 4, d. 6, e. 8

e