Correct Answer:
C. Rare
This question tests your knowledge of English synonyms. A synonym is a word that has the same or nearly the same meaning as another word. The adjective "infrequent" describes something that happens only occasionally or at long intervals.
Among the given options, "rare" is the closest synonym because it also means uncommon or occurring only occasionally. The other options do not match the meaning. Never means not at any time, usual means common or ordinary, and sometimes is an adverb rather than a synonym.
- Infrequent: Not occurring often.
- Synonym: Rare.
- Antonym: Frequent.
Therefore, the correct answer is: "Rare".