Carlo is a minor character, but he provides an interesting contrast to the play’s hero. while the hero is not afraid of dying to defend his principles, carlo is willing to renounce what he believes in order to save his own life.
what kind of character is carlo?
foil
antagonist
protagonist

The correct answer is Foil

Explanation:

In literature, a foil character is a type of character that has a minor role in the development of the story; however, this type of character supports the development or actions of the main character or protagonist which includes highlighting the positive qualities of the main character by displaying opposite traits. Considering this, Carlo can be classified as a foil, not only because his role in the story is minor (opposite to the one of the antagonist/protagonist) but also because Carlo display traits that highlight the ones of the main character.

One organism benefits and the other isn't affected.

Hope this helps!

-Payshence