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: the size of a television screen is given as the length of the screen ' s diagonal. if the screens were flat, then the area of a square 19 - inch screen would be how many square inches greater than the area of a square 17 - inch screen ?
Options: a. 36, b. 4, c. 16, d. 38, e. 40
[A]: a


[Q]: Problem: in what ratio must a grocer mix two varieties of pulses costing rs. 15 and rs. 20 per kg respectively so as to get a mixture worth rs. 16.50 per kg ?
Options: a. 3: 7, b. 5: 7, c. 7: 3, d. 7: 5, e. none
[A]: c


[Q]: Problem: two diagonals of a rhombus are 72 cm and 30 cm respectively. what is its perimeter ?
Options: ['a. 136 cm', 'b. 156 cm', 'c. 144 cm', 'd. 121 cm', 'e. 126 cm']
[A]:
b