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: an error 4 % in excess is made while measuring the side of a square . the percentage of error in the calculated area of the square is : 
Options: a ) 4.16 , b ) 5.16 , c ) 7.16 , d ) 8.16 , e ) 9.16
[A]: d


[Q]: Problem: 30 is what percent of 100 ? 
Options: a ) 35 % , b ) 30 % , c ) 45 % , d ) 50 % , e ) 55 %
[A]: b


[Q]: Problem: a broker invested her own money in the stock market . during the first year , she increased her stock market wealth by 90 percent . in the second year , largely as a result of a slump in the stock market , she suffered a 50 percent decrease in the value of her stock investments . what was the net increase or decrease on her overall stock investment wealth by the end of the second year ? 
Options: a ) − 5 % , b ) 5 % , c ) 15 % , d ) 20 % , e ) 80 %
[A]:
a