In which of the following cases, the direction of back bonding is from central atom to surrounding atom?

Back bonding in ${\mathrm{OCl}}_2$occurs from the centre atom to the surrounding atom. The fact that chlorine already contains a lone pair of electrons prevents the $\mathrm{p} \mathrm{pi}-\mathrm{d} \mathrm{pi}$ backbonding from being possible in the ${\mathrm{OCl}}_2$molecule (3 in fact).