Kinetic Theory question for JEE Main (JEE Main 2020 (4 Sep, Shift 1)), with solution

Match the $\dfrac{C_p}{C_v}$ ratio for ideal gases with different type of molecules:

$$\begin{array}{|l|l|}\hline \text{Molecule type} & C_p/C_v \\ \hline \text{(A) Monoatomic} & \text{(I) } 7/5 \\ \hline \text{(B) Diatomic rigid molecules} & \text{(II) } 9/7 \\ \hline \text{(C) Diatomic non-rigid molecules} & \text{(III) } 4/3 \\ \hline \text{(D) Triatomic rigid molecules} & \text{(IV) } 5/3 \\ \hline \end{array}$$