<!DOCTYPE html>
<html lang="en-US">
<head>
<style>
#point:after{
content:"\0003F";
}
</style>
</head>
<body>
<p>Question Mark using Hexa Decimal: ?</p>
<p>Question Mark using HTML Code: ?</p>
<p>Question Mark using HTML Entity: ?</p>
<p id="point">Question Mark using CSS Entity: </p>
</body>
</html>