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: what is the value of 3 x ^ 2 − 1.8 x + 0.8 for x = 0.6 ? 
Options: a ) − 0.3 , b ) 0.8 , c ) 0.3 , d ) 1.08 , e ) 2.46
Example Output: b

Example Input: Problem: caleb spends $ 64.50 on 50 hamburgers for the marching band . if single burgers cost $ 1.00 each and double burgers cost $ 1.50 each , how many double burgers did he buy ? 
Options: a ) 29 , b ) 10 , c ) 20 , d ) 40 , e ) 45
Example Output: a

Example Input: Problem: 5020 − ( 502 ÷ 100.4 ) = ? 
Options: a ) 15 , b ) 20 , c ) 5015 , d ) 25 , e ) 35
Example Output:
c