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?	Choose the correct answer:
A) 5 %  B) 10 %  C) 15 %  D) 14 %  E) 4 %

Rationale: "let diameter of circle r , dr = 20 and diameter of circle s , ds = 100 radius of circle r , rr = 10 radius of circle s , rs = 50 area of circle r / area of circle s = ( pi * rr ^ 2 ) / ( pi * rs ^ 2 ) = ( 10 / 50 ) ^ 2 = ( 2 / 10 ) ^ 2 = 4 % answer : e"
Answer: E