Question

How might an author make a character the antagonist in a story?
a. by making her evil.
b. by having her change during the course of a story.
c. by having her act as a sidekick to the protagonist.
d. by putting her in conflict with the hero.

Answer 1

An antagonist means someone who is actively against or opposes someone or something. 
To make a character an antagonist in a story, the most likable choice would be D. By putting her in conflict with the hero. Because that would make them meet against each other face to face to disagree and create a turning point.

Answer 2

d is the apex answer