Include files must have the file extension ".inc"

In PHP you can use both single quotes ( ' ' ) and double quotes ( " " ) for strings:

What is the correct way to create a function in PHP?

What is the correct way to connect to a MySQL database?

What is the correct way to add 1 to the $count variable?

PHP can be run on Microsoft Windows IIS(Internet Information Server):

Which one of these variables has an illegal name?

Which of the following regular expressions will match the string no.no.no?