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: if x ^ 2 – 4 x = 5, then one possible value of x – 2 =
Options: a. - 9, b. - 5, c. - 3, d. - 1, e. 5
[EX A]: c

[EX Q]: Problem: if the range q of the 6 numbers 4, 314, 710 and x is 12, what is the difference between the greatest possible value of x and least possible value of x ?
Options: a. 0, b. 2, c. 12, d. 13, e. 15
[EX A]: d

[EX Q]: Problem: the c. p of 10 pens is equal to the s. p of 5 pens. find his gain % or loss % ?
Options: a. 50 %, b. 40 %, c. 30 %, d. 60 %, e. 20 %
[EX A]:
a