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.

[Q]: Problem: three 6 faced dice are thrown together. the probability that exactly two dice show the same number on them is
Options: a. 5 / 15, b. 5 / 12, c. 5 / 19, d. 5 / 12, e. 5 / 11
[A]: b


[Q]: Problem: a 270 metres long bullet train running at the speed of 120 kmph crosses another bullet train running in opposite direction at the speed of 80 kmph in 9 seconds. what is the length of the other bullet train ?
Options: a. 226, b. 230, c. 430, d. 310, e. 260
[A]: b


[Q]: Problem: what is the units digit of 23 ^ 2 * 17 ^ 2 * 39 ^ 2 ?
Options: a. 1, b. 3, c. 5, d. 7, e. 9
[A]:
a