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: in 2000 there were 10000 women stockbrokers in the united states . by 2005 the number had increased to 20000 . approximately what was the percent increase ? 
Options: a ) 1 % , b ) 2 % , c ) 1.5 % , d ) 3 % , e ) 4 %
Example Output: a

Example Input: Problem: it takes 30 days to fill a laboratory dish with bacteria . if the size of the bacteria doubles each day , how long did it take for the bacteria to fill one sixteenth of the dish ? 
Options: a ) 16 days , b ) 26 days , c ) 27 days , d ) 28 days , e ) 29 days
Example Output: b

Example Input: Problem: in 1950 , richard was 4 times as old as robert . in 1955 , richard was 3 times as old as robert . in which year was richard 1.3 times as old as robert ? 
Options: a ) 1960 , b ) 1965 , c ) 1970 , d ) 1975 , e ) 2040
Example Output:
e