In the given figure, ABCD is a rhombus. Then,
Since, we know that the diagonals of a rhombus bisect each other at 90°.
Hence, OA = 
AC, OB = 
BD and ∠AOB = 90°
AB2 = OA2 + OB2
AB2 = (
AC)2 + (
BD)2
= 
(AC)2 + 
(BD)2
AB2 = 
(AC2 + BD2)
4AB2 = (AC2 + BD2)
∴ Option C is correct
25