Final answer:
White phosphorus consists of tetrahedral P4 molecules due to covalent bonds between phosphorus atoms, while nitrogen consists of diatomic N2 molecules due to a triple bond between nitrogen atoms.
Correct option is a.
Step-by-step explanation:
White phosphorus consists of tetrahedral P4 molecules because each phosphorus atom forms covalent bonds with three other phosphorus atoms. In a tetrahedron, there are four vertices, each representing a phosphorus atom. In contrast, nitrogen consists of diatomic N2 molecules because each nitrogen atom forms a triple bond with another nitrogen atom, resulting in a molecule with two nitrogen atoms joined by a triple bond.