How can someone get access to an HTML test bed? O They can be purchased online.
They are free and are available online.
They are free and can be obtained at computer stores.
They can be purchased at computer stores.

They are free and are available online.

Explanation:

Example: https://www.jmarshall.com/easy/html/testbed.html

answer is:

a). backstage view

explanation:

backstage view is the area where files and data about them is managed— creating, saving, printing, sending to others, inspecting for hidden metadata or personal information, and setting options. so in this way we can add many things to our document swiftly.

i hope you get the idea.