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: if 213 × 16 = 3408 , then 16 × 21.3 is equal to : 
Options: a ) 0.3408 , b ) 3.408 , c ) 34.08 , d ) 340.8 , e ) none of these
Example Output: d

Example Input: Problem: a car ferry can hold up to 70 tons of cargo . what is the greatest number of vehicles that the ferry can carry if half the vehicles are cars with an average ( arithmetic mean ) weight of 0.75 tons and half of the vehicles are trucks with an average ( arithmetic mean ) weight of 4 tons ? 
Options: a ) 14 , b ) 20 , c ) 28 , d ) 32 , e ) 36
Example Output: c

Example Input: Problem: a , b and c are partners . a receives 2 / 3 of profits , b and c dividing the remainder equally . a ' s income is increased by rs . 400 when the rate to profit rises from 5 to 7 percent . find the capital of b ? 
Options: a ) 3999 , b ) 7799 , c ) 2500 , d ) 5000 , e ) 2912
Example Output:
d