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'.

Example Input: Problem: vijay sells a cupboard at 10 % below cost price . had he got rs . 1500 more , he would have made a profit of 10 % . what is the cost price of the cupboard ? 
Options: a ) 7450 , b ) 7500 , c ) 7400 , d ) 7500 , e ) none of these
Example Output: b

Example Input: Problem: a shopkeeper loses 15 % , if an article is sold for rs . 136 . what should be the selling price of the article to gain 20 % ? 
Options: a ) s . 147 , b ) s . 148 , c ) s . 144 , d ) s . 189 , e ) s . 192
Example Output: e

Example Input: Problem: how many ounces of a 60 % salt solution must be added to 70 ounces of a 20 percent salt solution so that the resulting mixture is 40 % salt ? 
Options: a ) 16.67 , b ) 30 , c ) 50 , d ) 60.33 , e ) 70
Example Output:
e