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 \(v_{\text {final }}=\sqrt{3} v_{\text {old }} \Rightarrow v_2=\sqrt{3} v_1\)