A pioneer of a reform movement:
Answer with explanationAnswer: Option A
The one-word substitution is Apostle.
Apothecary: a person who prepared and sold medicines and drugs.
Apotheosis: the highest point in the development of something; a culmination or climax.
Renegade: a person who deserts and betrays an organization, country, or set of principles.
Apostle: a vigorous and pioneering advocate or supporter of a particular policy, idea, or cause.