In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: in a company of 160 employees , 90 are females . a total of 80 employees have advanced degrees and the rest have a college degree only . if 40 employees are males with college degree only , how many employees are females with advanced degrees ? 
Options: a ) 40 , b ) 45 , c ) 50 , d ) 55 , e ) 60
Example Output: c

Example Input: Problem: 12 business executives and 7 chairmen meet at a conference . if each business executive shakes the hand of every other business executive and every chairman once , and each chairman shakes the hand of each of the business executives but not the other chairmen , how many handshakes would take place ? 
Options: a ) 150 , b ) 131 , c ) 115 , d ) 90 , e ) 45
Example Output: a

Example Input: Problem: the ratio of the radius of two circles is 1 : 3 , and then the ratio of their areas is ? 
Options: a ) 1 : 5 , b ) 1 : 6 , c ) 1 : 9 , d ) 1 : 3 , e ) 1 : 2
Example Output:
c