A difference between an argumentative essay and an informative essay is that an informative essay is to have seven paragraphs and an argumentative three
paragraphs
an informative essay has two sentences to write from the prompt and an
argumentative essay has one sentence to write from the prompt before you read
your sources
an informative essay is to inform or teach and an argumentative essay is to
persuade or argue

The last option; An informative essay is to inform or teach and an argumentative essay is to persuade or argue

Explanation:

the purpose of the heading in the passage is to identify who is telling the story.

this excerpt is part of the book sugar changed the world (2010) written by marc aronson and marina budhos. as the book has been written by two people, the heading "marc" indicates that this specific excerpt is being narrated by aronson. in the fragment, marc describes his grandfather's story after hearing it from his cousin. however, there are other excerpts where budhos is the one that tells the story of her family.

aronson and budhos, who are husband and wife in real life, decided to write sugar changed the world when they found out how sugar, which had an important role in slavery and economy, changed their ancestors' lives.