If the protagonist of a story faces an external conflict with another person, what plot event would most likely cause him to develop as a character?

A compromise

Explanation:

The options you were given are the following:

An external conflict is a conflict that takes place between the protagonist and some outside force, most often the antagonist or society. The plot event that would most likely cause the protagonist to develop as a character is a compromise. Instead of completely going against his opponent, he could try understanding his side and work with him in order to find a solution the both of them could benefit from. This scenario would build empathy, compassion, and other virtues within the protagonist.

well since i don't know any of the following websites since you didn't list any. ima take a hard guess at it and say national geographic .org