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: a water tank , having the shape of a rectangular prism of base 100 square centimeters , is being filled at the rate of 1 liter per minute . find the rate at which the height of the water in the water tank increases . express your answer in centimeters per minute . 
Options: ['a ) 30 cm', 'b ) 10 cm', 'c ) 50 cm', 'd ) 90 cm', 'e ) 70 cm']

Ex Output:
b


Ex Input:
Problem: if y is the smallest positive integer such that 3,675 multiplied by y is the square of an integer , then y must be 
Options: a ) 2 , b ) 5 , c ) 6 , d ) 7 , e ) 12

Ex Output:
e


Ex Input:
Problem: how much greater is the combined area in square inches of the front and back of a rectangular sheet of paper measuring 11 inches by 17 inches than that of a rectangular sheet of paper measuring 8.5 inches by 11 inches ? 
Options: a ) 50 % , b ) 87 % , c ) 100 % , d ) 187 % , e ) 200 %

Ex Output:

c