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: if the radius of a cylinder is made 3 times and so is the height, what is the new volume of the cylinder divided by the old one ?
Options: a. 27., b. 2., c. 6., d. 4., e. 10.
[A]: a

[Q]: Problem: an 80 - liter solution of cool - drink is made from 10 % jasmine water. if 5 liters of jasmine and 15 liters of water were added to the solution, what percent of the solution is jasmine ?
Options: a. 11 %, b. 13 %, c. 15 %, d. 17 %, e. 19 %
[A]: b

[Q]: Problem: at an election 2 candidates are participated and a candidate got 20 % of votes and defeated by 500. and 10 votes are invalid. find the total polled votes ?
Options: a. 843, b. 1023, c. 965, d. 413, e. 1245
[A]:
a