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

Problem: if the diameter of circle r is 20 % of the diameter of circle s , the area of circle r is what percent of the area of circle s ? 
Options: a ) 5 % , b ) 10 % , c ) 15 % , d ) 14 % , e ) 4 %
e

Problem: if the area of a triangle with base 6 cm is equal to the area of a square with side 6 cm , then the altitude of the triangle is 
Options: ['a ) 12 cm', 'b ) 10 cm', 'c ) 11 cm', 'd ) 15 cm', 'e ) 20 cm']
a

Problem: what is the smallest positive perfect square that is divisible by 4 , 9 , and 18 ? 
Options: a ) 36 , b ) 81 , c ) 144 , d ) 625 , e ) 900

a