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

Problem: what is the square root of 6,561 ? 
Options: a ) 18 , b ) 9 , c ) 45 , d ) 62 , e ) 81
e

Problem: if x and y are sets of integers , x # y denotes the set of integers that belong to set x or set y , but not both . if x consists of 12 integers , y consists of 18 integers , and 6 of the integers are in both x and y , then x # y consists of how many integers ? 
Options: a ) 6 , b ) 16 , c ) 18 , d ) 30 , e ) 174
c

Problem: in the biotechnology class of 2000 , there were x graduates . 32 of the graduates found a job , 45 continued on to their second degree and 13 did both . if only 9 people did n ' t do both , what is x equal to ? 
Options: a ) 69 . , b ) 71 , c ) 73 , d ) 75 , e ) 76

c