When a string is divided into three segments of length $l_1,\; l_2 \;and\; l_3$, the fundamental frequencies of these three segments are $v_1, \;v_2 \;and \;v_3$ respectively. The original functamental frequency (v) of the string is :

Question

( A ) $\sqrt{v}=\sqrt{v_1}+\sqrt{v_2}+\sqrt{v_3}$
( B ) $\frac{1}{\sqrt v}$=$\frac{1}{\sqrt v_1}+\frac{1}{\sqrt v_2}+\frac{1}{\sqrt v_3}$
( C ) $v=v_1+v_2+v_3$
( D ) $\frac{1}{v}$=$\frac{1}{v_1}+\frac{1}{v_2}+\frac{1}{v_3}$