the proper style for an argumentative essay is academic. friendly. informal. personal.

Brief Explanations:

An argumentative essay is a formal piece of writing. It requires presenting a clear thesis, supporting it with evidence, and addressing counter - arguments. A friendly, informal, or personal style is not appropriate as it may lack the objectivity and rigor needed. An academic style ensures clarity, logical flow, and the use of proper citation (if any), which are essential for an argumentative essay.

Answer:

academic.