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 ratio of the radius of two circles is 1 : 3 , and then the ratio of their areas is ? 
Options: a ) 1 : 5 , b ) 1 : 6 , c ) 1 : 9 , d ) 1 : 3 , e ) 1 : 2
[A]: c


[Q]: Problem: 80 pie square inches of material of negligible thickness are required to construct a 1 / 16 scale model of a cylindrical barrel . if the diameter of the base of the barrel is 160 inches , then what is the volume of the barrel , to the nearest cubic foot ? 
Options: ['a ) 2 pie', 'b ) 11 pie', 'c ) 178 pie', 'd ) 711 pie', 'e ) 1280 pie']
[A]: c


[Q]: Problem: if n is the smallest integer such that 144 times n is the square of an integer , what is the value of n ? 
Options: a ) 2 , b ) 3 , c ) 6 , d ) 12 , e ) 24
[A]:
a