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'.

Q: Problem: what is the rate percent when the simple interest on rs . 4000 amount to rs . 320 in 2 years ? 
Options: a ) 4 % , b ) 4.1 % , c ) 4.2 % , d ) 4.3 % , e ) 4.5 %

A: a
****
Q: Problem: the cost price of a radio is rs . 2550 and it was sold for rs . 2130 , find the loss % ? 
Options: a ) 18 , b ) 10 , c ) 15 , d ) 66 , e ) 41

A: c
****
Q: Problem: a bag marked at $ 200 is sold for $ 120 . the rate of discount is ? 
Options: a ) 10 % , b ) 25 % , c ) 20 % , d ) 50 % , e ) 40 %

A:
e
****