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'.

Ex 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

Ex Output:
b


Ex Input:
Problem: the mean of 40 observations was 100 . it was found later that an observation 50 was wrongly taken as 75 the corrected new mean is 
Options: a ) 125.8 , b ) 102.8 , c ) 99.375 , d ) 100.52 , e ) 122

Ex Output:
c


Ex Input:
Problem: given f ( x ) = 3 x – 5 , for what value of x does 2 * [ f ( x ) ] – 19 = f ( x – 4 ) ? 
Options: a ) 2 , b ) 4 , c ) 6 , d ) 8 , e ) 10

Ex Output:

b