historical fiction is a gender based on historical fiction, _____.
which is the best way to complete the sentence above?
To complete the sentence, the best way would be to fill in the blank with a noun or noun phrase that properly identifies what historical fiction is based on. One possible completion could be:
"historical fiction is a genre based on historical events and settings."
In this context, "genre" is the appropriate term as it refers to a category or type of artistic composition, in this case, historical fiction.