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: find the value of ( 55 + 113 / 78 ) × 78 
Options: a ) 4423 , b ) 4403 , c ) 4413 , d ) 2403 , e ) 4375
Example Output: b

Example Input: Problem: if one root of the equation 2 x ^ 2 + 3 x – k = 0 is 5 , what is the value of k ? 
Options: a ) 65 , b ) 79 , c ) 68 , d ) 87 , e ) 90
Example Output: a

Example Input: Problem: the price of commodity x increases by 30 cents every year , while the price of commodity y increases by 20 cents every year . if in 2001 , the price of commodity x was $ 4.20 and the price of commodity y was $ 4.50 , in which year will commodity x cost 90 cents more than the commodity y ? 
Options: a ) 2010 , b ) 2011 , c ) 2012 , d ) 2013 , e ) 2014
Example Output:
d