Depending on the context, a rhetorical question may be punctuated by a question mark (?), full stop (.), or exclamation mark (!),[REF] but some sources argue that it is required to use a question mark for any question, rhetorical or not [REF].
In the 1580s, English printer Henry Denham invented a "rhetorical question mark" for use at the end of a rhetorical question; however, it fell out of use in the 17th century.