Simple molecular substances consist of discrete molecules with weak intermolecular forces.

Steps:

• Identify simple molecular structures: discrete molecules like I₂ (iodine) or C₆₀ (fullerene), not extended lattices.
• Classify C₆₀: a soccer-ball-shaped carbon molecule, simple molecular.
• Classify iodine: diatomic I₂ molecules, simple molecular.
• Compare pairs: only A has both as discrete molecules; others include giant covalent structures like graphene (2D carbon sheet) or graphite (3D layers).

Why A is correct:

• Both C₆₀ and iodine form discrete molecules held by van der Waals forces, fitting the definition of simple molecular substances.

Why the others are wrong:

• B: Graphene is giant covalent (extended covalent bonds), not simple molecular.
• C: Both graphene and graphite are giant covalent structures.
• D: Graphite is giant covalent, not simple molecular.

Final answer: A