[98a.] Place a question mark after a direct question, but not after an indirect question.

[Note.]—When the main sentence which introduces an indirect question is itself interrogatory, a question mark follows.

[b.] A question mark is often used within a sentence, but should not be followed by a comma, semicolon, or period.

[c.] A question mark within parentheses may be used to express uncertainty as to the correctness of an assertion.

[d.] The use of a question mark as a label for humor or irony is childish.