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

[EX Q]: Problem: if each edge of a cube is doubled , then its volume :
Options: ['a ) becomes 8 times', 'b ) becomes 9 times', 'c ) is double', 'd ) becomes 6 times', 'e ) none']
[EX A]: a

[EX Q]: Problem: 10 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 ) 144 , b ) 131 , c ) 115 , d ) 90 , e ) 45
[EX A]: c

[EX Q]: Problem: what is the measure of the radius of the circle that circumscribes a triangle whose sides measure 9 , 40 and 41 ?
Options: a ) 6 , b ) 4 , c ) 24.5 , d ) 20.5 , e ) 12.5
[EX A]:
d