The verb is past participle so that would be option A.
Answer:
Use a preferred style guide
Include in-text citations
Include a reference page
Explanation:
These are the three things that are definitly needed to correctly cite a source correctly.
Credibility has nothing to do with citing the source correctly.
summarized information is not the only way you can cite work. you can paraphrase or direct quote sources.
Sentence A Uses a colon correctly.
