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: at what rate percent per annum will the simple interest on a sum of money be 2 / 5 of the amount in 10 years ? 
Options: a ) 4 % , b ) 74 % , c ) 64 % , d ) 74 % , e ) 94 %

A: a
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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
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Q: Problem: john had a stock of 900 books in his bookshop . he sold 75 on monday , 50 on tuesday , 64 on wednesday , 78 on thursday and 135 on friday . what percentage of the books were not sold ? 
Options: a ) 50.4 % , b ) 23.8 % , c ) 66.5 % , d ) 34.9 % , e ) 55.3 %

A:
e
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