Final answer:
The correct filename that follows the naming procedure for filenames used on the Web is 'myfirstwebsite.html'.
Step-by-step explanation:
The correct filename that follows the naming procedure for filenames used on the Web is myfirstwebsite.html.
According to the given information, filenames on the Web should be written in lowercase letters, without spaces or special characters. In this case, 'myfirstwebsite.html' adheres to these rules.
Other options such as 'my first website.html', 'my.first.website.html', and 'my#1website.html' violates the naming procedure by including spaces, periods, and special characters.