Correct Answer - A
Among the given elements, Cl has maximum tendency of `ppi-dpi` bonding. On moving across the period, nuclear charge increases and more s, p electrons are added. Due to incomplete shielding of nuclear charge, the atomic size and so the size of 3d-orbitals decreases from `Si to P to S to Cl`. Decrease in size of 3d-orbitals leads to stronger `ppi-dpi` overlap.
