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 Input:
Problem: the length of a rectangle is halved , while its breadth is tripled . what is the % change in area ? 
Options: a ) 30 % , b ) 40 % , c ) 50 % , d ) 60 % , e ) 65 %

Ex Output:
c


Ex 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

Ex Output:
a


Ex Input:
Problem: the parameter of a square is equal to the perimeter of a rectangle of length 20 cm and breadth 14 cm . find the circumference of a semicircle whose diameter is equal to the side of the square . ( round off your answer to two decimal places ) 
Options: a ) 77.14 cm , b ) 47.14 cm , c ) 26.71 cm , d ) 94.94 cm , e ) 23.57 cm

Ex Output:

c