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

[Q]: Problem: the radius of a cylinder is 2 r units and height is 3 r units . find the curved surface ? 
Options: a ) 18 π r 2 , b ) 12 π r 2 , c ) 3 π r 2 , d ) 6 π r 2 , e ) 9 π r 2
[A]: b


[Q]: Problem: in a rectangular metallic piece of paper that covers exactly the area of a cube . the length of the piece of paper is 48 inches and the width is 72 inches . what is the volume of the cube in cubic feet is 1 feet is 12 inches ? 
Options: ['a ) a 8', 'b ) b 22', 'c ) c 27', 'd ) d 40', 'e ) e 51']
[A]: a


[Q]: Problem: the sides of a cube measures 6.5 cm . if the surface area of the cube is the same as a ball , what is the radius of the ball ? round to the nearest whole number . 
Options: ['a ) 9', 'b ) 7', 'c ) 4', 'd ) 8', 'e ) 6']
[A]:
c