TASK DEFINITION: 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.
PROBLEM: Problem: a fraudulent dairy guy declares to market his dairy at price range but he combined it with water and therefore benefits 25 %. the percentage of water in the combination is :
Options: a. 20 %, b. 30 %, c. 50 %, d. 35 %, e. 60 %

SOLUTION: a

PROBLEM: Problem: if a man lost 8 % by selling oranges at the rate of 25 a rupee at how many a rupee must he sell them to gain 25 % ?
Options: a. 20, b. 15, c. 18.4, d. 20, e. 12.8

SOLUTION: c

PROBLEM: Problem: if a is a positive integer, and if the units digit of a ^ 2 is 9 and the units digit of ( a + 1 ) ^ 2 is 4, what is the units g digit of ( a + 2 ) ^ 2 ?
Options: a. 1, b. 3, c. 5, d. 6, e. c. 14

SOLUTION:
a