The diagonals of the two squares are in the ratio of 2:5 find the ratio of their area .  Choose the correct answer:  A) 5 : 89  B) 7 : 96  C) 4 : 25  D) 5 : 84  E) 8 : 96

Rationale: "let the diagonals of the square be 2 x and 5 x respectively . ratio of their areas = 1 / 2 ( 2 x ) ^ 2 : 1 / 2 ( 5 x ) = 4 x ^ 2 : 25 x ^ 2 = 4 : 25 answer ( c )"
Answer: C