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 120 % of 13 / 24 of 840 ? 
Options: a ) 436 , b ) 478 , c ) 512 , d ) 546 , e ) 620
[A]: d


[Q]: Problem: walking 7 / 6 of his usual rate , a boy reaches his school 3 min early . find his usual time to reach the school ? 
Options: a ) 21 , b ) 28 , c ) 99 , d ) 77 , e ) 66
[A]: a


[Q]: Problem: the market value of a 10.5 % stock , in which an income of rs . 756 is derived by investing rs . 6500 , brokerage being 1 / 4 % , is : 
Options: a ) 90.03 , b ) 114 , c ) 114.75 , d ) 124 , e ) 124.75
[A]:
a