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 simple interest on a certain amount in at 4 % rate 5 years amounted to rs. 2240 less than the principal. what was the principal ?
Options: a. 1500, b. 2500, c. 2507, d. 2800, e. 11500
[EX A]: d

[EX Q]: Problem: ramesh purchased a refrigerator for rs. 12500 after getting a discount of 20 % on the labelled price. he spent rs. 125 on transport and rs. 250 on installation. at what price should it be sold so that the profit earned would be 18 % if no discount was offered ?
Options: a. 17608, b. 17606, c. 17604, d. 17600, e. 18880
[EX A]: e

[EX Q]: Problem: a ' s speed is 20 / 13 times that of b. if a and b run a race, what part of the length of the race should a give b as a head start, so that b beats a by 80 % of the length of the race ?
Options: a. 44 %, b. 48 %, c. 52 %, d. 42 %, e. 87 %
[EX A]:
e