Given below are two statements : One is labelled as Assertion A and other is labelled as Reason R. Assertion A : The dihedral angles in $\mathrm{H}_2 \mathrm{O}_2$ in gaseous phase is $90.2^{\circ}$ and in solid phase is $111.5^{\circ}$. Reason R . The change in dihedral angle in solid and gaseous phase is due to the difference in the intermolecular forces.
Choose the most appropriate answer from the options given below for A and R.