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: if the sides of a cube are in the ratio 5: 3. what is the ratio of their diagonals ?
Options: ['a. 5: 9', 'b. 9: 3', 'c. 5: 4', 'd. 3: 5', 'e. 5: 3']
[EX A]: e

[EX Q]: Problem: a certain library assesses fines for overdue books as follows. on the first day that a book is overdue, the total fine is $ 0.09. for each additional day that the book is overdue, the total fine is either increased by $ 0.30 or doubled, whichever results in the lesser amount. what is the total for a book on the fourth day it is overdue ?
Options: a. $ 0.66, b. $ 0.70, c. $ 0.80, d. $ 0.90, e. $ 1.00
[EX A]: a

[EX Q]: Problem: in a class of 40 students 26 play football and play 20 long tennis, if 17 play above, many play neither ?
Options: a. 6, b. 8, c. 10, d. 11, e. 14
[EX A]:
d