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 x + ( 1 / x ) = 5 , what is the value of w = x ^ 2 + ( 1 / x ) ^ 2 ? 
Options: a ) w = 21 , b ) w = 22 , c ) w = 23 , d ) w = 24 , e ) 27

Ex Output:
c


Ex Input:
Problem: evaluate 64 / . 08 
Options: a ) 800 , b ) 500 , c ) 505 , d ) none of these , e ) 506

Ex Output:
a


Ex Input:
Problem: a multiple choice test consists of 4 questions , and each question has 5 answer choices . in how many q ways can the test be completed if every question is unanswered ? 
Options: a ) 24 , b ) 120 , c ) 625 , d ) 720 , e ) 1024

Ex Output:

c