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: ( 112 x 5 ^ 4 ) = ? 
Options: a ) 70000 , b ) 80000 , c ) 90000 , d ) 90090 , e ) 100000
Example Output: a

Example Input: Problem: ages of two sisters differ by 9 years . if 5 years ago , the elder one was twice as old the younger one , find their present age 
Options: a ) 1228 , b ) 1423 , c ) 1632 , d ) 1834 , e ) 1932
Example Output: b

Example Input: Problem: in a renowned city , the average birth rate is 4 people every two seconds and the death rate is 2 people every two seconds . estimate the size of the population net increase that occurs in one day . 
Options: a ) 86,400 , b ) 172,800 , c ) 468,830 , d ) 338,200 , e ) 259,200
Example Output:
a