Good Question. A historical argument may be anything from what you think of a past event or your own verbal opinion on an event in the past. No matter what the situation is, the argument is about an event that happened in the PAST. The "PAST" is the key term for answering your question.
However, I looked online to see if/what multiple choice options you may have or have forgotten to put in the question.
"<span>An explanation for why a past event happened" </span> I take NO Responsibility/Credit for the quoted answer above.
I am only here to help, not to get into trouble. I hope you understand.