What is the ratio between perimeters of two squares one having 2.5 times the diagonal then the other? Choose the correct choice from the following answers:
A) 4 : 5  B) 1 : 3  C) 2.5 : 1  D) 3.5 : 1  E) 3 : 2

Rationale: "d = 2.5 d d = d a √ 2 = 2.5 d a √ 2 = d a = 2.5 d / √ 2 a = d / √ 2 = > 2.5 : 1 answer : c"
Answer: C