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'.

Problem: at a particular graduation party with 300 guests , 70 % of the guests brought gifts , and 40 % of the female guests brought gifts . if 15 males did not bring gifts to the party , how many females did bring gifts ? 
Options: a ) 18 , b ) 28 , c ) 50 , d ) 68 , e ) 70
c

Problem: if the cost price of 50 articles is equal to the selling price of 20 articles , then the gain or loss percent is ? 
Options: a ) 16 , b ) 127 , c ) 12 , d ) 18 , e ) 150
e

Problem: the sale price of an article including the sales tax is rs . 616 . the rate of sales tax is 10 % . if the shopkeeper has made a profit of 12 % , then the cost price of the article is 
Options: a ) rs . 500 , b ) rs . 515 , c ) rs . 550 , d ) rs . 600 , e ) none

a