if an argumentative essay contains reasoning, then the reasoning in the essay is based on faulty logic…

Brief Explanations:

The term "fallacious" means based on a mistaken belief or containing a logical error. In the context of an argumentative essay, fallacious reasoning implies faulty logic. Appropriate, compelling, and legitimate reasoning are all positive - indicating correct or strong logic, while fallacious is the one related to faulty logic.

Answer:

C. fallacious