In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: i sold a book at a profit of 10 % . had i sold it for $ 150 more , 15 % would have been gained . find the cost price ? 
Options: a ) $ 2000 , b ) $ 2500 , c ) $ 3000 , d ) $ 3120 , e ) $ 1540

Ex Output:
c


Ex Input:
Problem: find the annual income derived by investing $ 6800 in 30 % stock at 136 . 
Options: a ) 550 , b ) 1500 , c ) 250 , d ) 1300 , e ) 400

Ex Output:
b


Ex Input:
Problem: boy sells a book for rs . 540 he gets a loss of 10 % , to gain 10 % , what should be the sp ? 
Options: a ) 430 , b ) 450 , c ) 550 , d ) 590 , e ) 660

Ex Output:

e