Question mark ???

This is what I found out when I researched this....When early scholars wrote in Latin, they would place the word questio – meaning "question" – at the end of a sentence to indicate a query. To conserve valuable space, writing it was soon shortened to qo, which caused another problem – readers might mistake it for the ending of a word. So they squashed the letters into a symbol: a lowercased q on top of an o. Over time the o shrank to a dot and the q to a squiggle, giving us our current question mark.

yes it could be any thing but when this symbol came into existence it was meant for question mark and all other symbols came into exist with their own meaning.

It is the sign's destiny to be the question mark. That is what I think because if "#" was the question mark then this sign destined to be the question mark.

Because the sign "$" gives safety,not makes you to ask questions...ha ha ha