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: a 340 - liter solution of kola is made from 88 % water, 5 % concentrated kola and the rest is made from sugar. if 3.2 liters of sugar, 10 liter of water and 6.8 liters of concentrated kola were added to the solution, what percent of the solution is made from sugar ?
Options: a. 6 %., b. 7.5 %., c. 9.2 %., d. 10.5 %., e. 11 %.
[EX A]: b

[EX Q]: Problem: if the population of a certain country increases at the rate of one person every 15 seconds, by how many persons does the population increase in 25 minutes ?
Options: a. 80, b. 100, c. 150, d. 240, e. 300
[EX A]: b

[EX Q]: Problem: if a man lost 4 % by selling oranges at the rate of 72 a rupee at how many a rupee must he sell them to gain 44 % ?
Options: a. 41, b. 48, c. 49, d. 44, e. 43
[EX A]:
b