Cure : Disease — select the pair that expresses the same relation and completes the analogy.

A cure is the thing applied to undo a disease, so the first word is the remedy and the second the harm it cancels. An antidote is given to undo the work of a poison. 'Vaccine : Immunity' puts a remedy first but follows it with the good result it brings about, not a harm it removes. 'Doctor : Patient' names two people, and 'Medicine : Chemist' names the man who sells the remedy rather than anything it acts upon.