c
(c)
$\omega_{\text {old }}=\sqrt{\frac{k_{\text {old }}}{m}}$
When divided into $3$ parts the spring constant of smaller parts
$\therefore k_{\text {final }}=3 k_{\text {old }}$
$\therefore \omega_{\text {linal }}=\sqrt{3} \omega_{\text {old }}$
$\omega=2 \pi v$
Hence $v_{\text {final }}=\sqrt{3} v_{\text {old }} \Rightarrow v_2=\sqrt{3} v_1$