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: there is one 4 - digit whole number n, such that the last 4 digits of n 2 are in fact the original number n
Options: a. 8476, b. 7376, c. 9376, d. 7378, e. 9466
[EX A]: c

[EX Q]: Problem: increasing the original price of a certain item by 25 percent and then increasing the new price by 30 percent is equivalent to increasing the original price by what percent ?
Options: a. 31.25, b. 37.5, c. 50.0, d. 52.5, e. 62.5
[EX A]: e

[EX Q]: Problem: ann and bob drive separately to a meeting. ann ' s average driving speed is greater than bob ' s avergae driving speed by one - third of bob ' s average driving speed, and ann drives twice as many miles as bob. what is the ratio e of the number of hours ann spends driving to the meeting to the number of hours bob spends driving to the meeting ?
Options: a. 8: 3, b. 3: 2, c. 4: 3, d. 2: 3, e. 3: 8
[EX A]:
b