For which pair of allotropes is one a molecular solid and the other a network covalent solid?

Because white phosphorous exhibits angular strain in the${\mathrm{P}}_4$ molecule, where the angles are only $60°$, it is more reactive than red phosphorous. Such an angular tension does not exist in red phosphorous.
Red phosphorous in this has a network covalent solid, and white Phosphorus has a molecular solid.