Online learning is impossible without

It should be all of them except for "the use of textbook".

Note that "the use of textbook" does not state that it is an 'online textbook', and so it can be ruled out.

You will need media literacy to be able to gain knowledge from information sources such as podcasts, videos, or other medias.
You will need internet connection to be able to access online information, hence "online learning".

hope this helps