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: a trader mixes 80 kg of tea at 15 per kg with 20 kg of tea at cost price of 20 per kg. in order to earn a profit of 25 %, what should be the sale price of the mixed tea ?
Options: a. 23.75, b. 22, c. 20, d. 19.20, e. none of these
c

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 %
b

Problem: the measure of the side of a square is quadrupled. if x represents the perimeter of the original square, what is the value of the new perimeter ?
Options: ['a. 3 x', 'b. 4 x', 'c. 9 x', 'd. 12 x', 'e. 27 x']

b