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 slant height of a cone is 21 cm and radius of the base is 10 cm , find the curved surface of the cone . 
Options: a ) 330 , b ) 770 , c ) 660 , d ) 100 , e ) 600

Ex Output:
c


Ex Input:
Problem: huey ' s hip pizza sells two sizes of square pizzas : a small pizza that measures 6 inches on a side and costs $ 10 , and a large pizza that measures 9 inches on a side and costs $ 20 . if two friends go to huey ' s with $ 30 apiece , how many more square inches of pizza can they buy if they pool their money than if they each purchase pizza alone ? 
Options: a ) 9 square inches , b ) 10 square inches , c ) 15 square inches , d ) 25 square inches , e ) 350 square inches

Ex Output:
a


Ex Input:
Problem: 30 square stone slabs of equal size were needed to cover a floor area of 50.7 sq . m . find the length of each stone slab ? 
Options: a ) 130 cm , b ) 767 cm , c ) 88 cm , d ) 666 cm , e ) 776 cm

Ex Output:

a