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: if ( 1 – 1.5 ) n = 1 , then n = 
Options: a ) − 400 , b ) − 140 , c ) − 2 , d ) 4 , e ) 400

Ex Output:
c


Ex Input:
Problem: if 45 - [ 28 - { 37 - ( 15 - * ) } ] = 59 , then * is equal to : 
Options: a ) - 29 , b ) - 19 , c ) 20 , d ) 29 , e ) 39

Ex Output:
c


Ex Input:
Problem: the average age of a group of persons going for picnic is years . fifteen new persons with an average age of 15 years join the group on the spot due to which their average age becomes 15.5 years . the number of persons initially going for picnic is 
Options: a ) 5 , b ) 10 , c ) 15 , d ) 40 , e ) 50

Ex Output:

c