What happens to covalent bonds when small molecular substances melt or boil?

The correct option is Covalent bonds remain intact. This answer is correct because it matches the approved learning objective to explain that covalent bonds inside molecules are not broken during melting or boiling in the subtopic Properties of small molecules.

The correct option is Covalent bonds remain intact. Covalent bonds remain intact is correct because it directly supports the approved learning objective to explain that covalent bonds inside molecules are not broken during melting or boiling. This belongs to the subtopic Properties of small molecules within How bonding and structure are related to the properties of substances, so the explanation must stay tied to that curriculum context. The other options are incorrect because they either do not answer this learning objective, use a vague statement, or move away from Properties of small molecules.