In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: a couple spent $ 211.20 in total while dining out and paid this amount using a credit card . the $ 211.20 figure included a 20 percent tip which was paid on top of the price which already included a sales tax of 10 percent on top of the price of the food . what was the actual price of the food before tax and tip ? 
Options: a ) $ 120 , b ) $ 140 , c ) $ 150 , d ) $ 160 , e ) $ 180
Example Output: d

Example Input: Problem: if x / y = 7 / 3 , then ( x + y ) / ( x - y ) = ? 
Options: a ) 5 , b ) 5 / 2 , c ) - 1 / 6 , d ) - 1 / 5 , e ) - 5
Example Output: b

Example Input: Problem: pradeep has to obtain 20 % of the total marks to pass . he got 160 marks and failed by 25 marks . the maximum marks are 
Options: a ) 1925 , b ) 600 , c ) 925 , d ) 1325 , e ) 900
Example Output:
c