A conducting rod of mass $m$ and length $l$ is connected by two identical springs as shown in Fig. $15.47$. Initially, the system is in equilibrium. A uniform magnetic field of magnitude $B$ directed perpendicular
to the plane of the paper outwards also exists in the region. If a current $I$ is switched on that passes from $P$ to $Q$ through the rod. Further maximum elongation in the spring is $[$ Given: $|m g|=|B I|]$
Fig.
(A) $\frac{B I l}{K}$
(B) $\frac{B I l}{4 K}$
(C) $\frac{B I l}{8 K}$
(D) $\frac{B I l}{16 K}$