If you have two questions, one embedded in the other, should there be a single, final question mark covering both the main question and the nested one, or one for each?
Here is an example:
A) Does anyone know the answer (or can anyone explain?) if there should be one or two question marks in this sentence?
Here is another example just to clarify:
B) Does anyone know the answer (or does anyone not know?)?
I am mainly concerned with the embedded question coming at the end of sentence like this: ...(...?)?
That looks really odd to me. It doesn't seem right; however, I feel that it looks fine if I have the nested question in the middle of the sentence, i.e. of the form:
C) Does anyone know the answer (or does anyone not know?) to this question?
The punctuation in C looks correct to me, if I take the first question mark out then it looks looks wrong, but it seems that B and C are exactly, but for the position of the parentheses, the equivalent of each other.
P.S. One last point, are single and double quotation marks considered to be parentheses?