A wire of length L is hanging from a fixed support. The length changes to L1 and L2 when masses 1kg and 2 kg are suspended respectively from its free end. Then the value of L is equal to :
(A) √ (L 1 L 2)
(B) L1 + L2/2
(C) 2L1 - L2
(D) L1 + L2/3