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.

[EX Q]: Problem: in a survey of 340 employees, 104 of them are uninsured, 54 work part time, and 12.5 percent of employees who are uninsured work part time. if a person is to be randomly selected from those surveyed, what is the probability that the person will neither work part time nor be uninsured ?
Options: a. 7 / 12, b. 8 / 41, c. 39 / 68, d. 1 / 8, e. 41 / 91
[EX A]: c

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

[EX Q]: Problem: in a box of 9 pens, a total of 3 are defective. if a customer buys 2 pens selected at random from the box, what is the probability that neither pen will be defective ?
Options: a. 3 / 10, b. 4 / 11, c. 5 / 12, d. 6 / 13, e. 7 / 15
[EX A]:
c