The only article among these options is an, and that is the correct answer - <em>an </em>is the indefinite article.
It, her, and that are pronouns.
Oral tradition is information passed down through the generations by word of mouth that is not written down. This includes historical and cultural traditions, literature and law. Explore some oral tradition examples like legends, proverbs, folktales, and customs.
An infinitive usually consists of the words "to" plus a verb in its simplest form. Which makes "to finish" seem like the most logical choice.
I hope this is correct and helps you :) good luck!