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: if a lends rs . 2000 to b at 15 % per annum and b lends the same sum to c at 17 % per annum then the gain of b in a period of 4 years is ? 
Options: a ) 155 , b ) 162 , c ) 157.5 , d ) 160 , e ) 157.12
[A]: d


[Q]: Problem: a man buys an article for $ 10 . and sells it for $ 30 . find the gain percent ? 
Options: a ) 25 % , b ) 50 % , c ) 20 % , d ) 150 % , e ) 300 %
[A]: e


[Q]: Problem: a tank contains 10,000 gallons of a solution that is 7 percent sodium chloride by volume . if 2,500 gallons of water evaporate from the tank , the remaining solution will be approximately what percent sodium chloride ? 
Options: a ) 1.25 % , b ) 3.75 % , c ) 9.33 % , d ) 10.67 % , e ) 11.7 %
[A]:
c