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 a is a positive integer , and if the units digit of a ^ 2 is 9 and the units digit of ( a + 1 ) ^ 2 is 4 , what is the units x digit of ( a + 2 ) ^ 2 ? 
Options: a ) 1 , b ) 3 , c ) 5 , d ) 6 , e ) c . 14
Example Output: a

Example Input: Problem: find the average of first 4 multiples of 15 ? 
Options: a ) 10 , b ) 12.6 , c ) 22.5 , d ) 31.3 , e ) 37.5
Example Output: e

Example Input: Problem: a library has an average of 510 visitors on sundays and 240 on other days . the average number of visitors per day in a month of 30 days beginning with a sunday is ? 
Options: a ) 285 , b ) 227 , c ) 271 , d ) 187 , e ) 199
Example Output:
a