In this task, you need to provide the correct option for a given problem from the provided options.

Ex Input:
Problem: in a class of 40 students 26 play football and play 20 long tennis , if 17 play above , many play neither ?
Options: a ) 6 , b ) 8 , c ) 10 , d ) 11 , e ) 14

Ex Output:
d

Ex Input:
Problem: evaluate 50 ! / 47 !
Options: a ) 102500 , b ) 112584 , c ) 117600 , d ) 118450 , e ) 128450

Ex Output:
c

Ex Input:
Problem: what is the value of ( log 2 3 ) ( log 3 4 ) ( log 4 5 ) . . . ( log 63 64 ) ?
Options: a ) 1 / 6 , b ) 2 , c ) 5 / 2 , d ) 6 , e ) 32

Ex Output:
d