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: the average of 11 10 prime numbers which are odd is ?
Options: a. 17.72, b. 18.52, c. 19.63, d. 16.53, e. 15.63
[EX A]: a

[EX Q]: Problem: if a man lost 10 % by selling oranges at the rate of 12 a rupee at how many a rupee must he sell them to gain 44 % ?
Options: a. 6.5, b. 7.5, c. 7, d. 8, e. 2
[EX A]: b

[EX Q]: Problem: if a number n is chosen at random from the set of two - digit integers whose digits are both prime numbers, what is the probability r that n is divisible by 3 ?
Options: a. 1 / 3, b. ¼, c. 9 / 25, d. 5 / 16, e. 0
[EX A]:
d