In his Nobel Prize acceptance speech, William Faulkner asserts that writers whose work focuses on the problems of the human heart in conflict with itself" and issues surrounding "universal truths" can ultimately
lead humanity into moral corruption and decay
O help humanity to not only endure but to prevail
O wash their hands of humanity's collective problems
O achieve for themselves great wealth and success

help humanity to not only endure but to prevail

Explanation:

Faulkner won Nobel Prize in 1949. and gave, what some claim to be, the best acceptance speech in Nobel Prize history.

Given in the aftermath of WWII, in the time if the great nuclear tensions during the Cold War, when people were afraid for their lives, this speech reminds the audience that writing out of fear is wrong and useless.

That's why, the mission of every poet or writer is to write about inner conflicts of a human heart and universal truths, such as love, honor, pity, pride, compassion, sacriface. Literature's purpose is to remind us of these things and give us hope to endure and prevail fear and hard times.

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.