In comparison to molecules that interact by London dispersion forces only, the melting point of similar-sized molecules forming hydrogen bonds would most likely be

Hydrogen bonds are stronger intermolecular attractions than London dispersion forces between similar-sized molecules. More energy is therefore needed to separate hydrogen-bonded molecules and melt the solid, so their melting point is most likely higher. The correct choice is D, “higher.”

AI-written and checked against the verified answer.