Saving and sending as a PDF or JPEG/PNG: This is quick and has its uses. If you save as a PDF all of your links will still work when the document is opened up. You will have to update the PDF and shared links every time you make a change. If you save as a JPEG or PNG it will only be a picture of your classroom.
View: anybody will see the presentation in Google Slides but will not be able to make changes unless they click -> file -> make a copy. Then they will have their own copy of the document. All changes you make in your slides will change automatically with the URL, but after they make a copy, they will no longer get the updates to the original in their copy.
Comment: Share with the ability to add comments, cannot make changes, not ideal for this.
Edit: Anybody you send the link to can make changes to your original. REALLY NOT Ideal for this.
Changing to Restricted Access: If this is selected instead of "everybody with the link can view" you will be sent an email to confirm and grant the view access. This has its uses, but it is not very fun for you to deal with. After a copy is made they will not have any of your live updates.
Preview: This is like view but you have to edit the URL slightly. Get the view share URL and change the share URL from /edit?usp=sharing to this /preview. This will make the document open up in a black window without all of the google slides features. In this mode all changes you make to your slide or presentation will automatically be changed with everybody the URL is shared with, you do not have to resend anything.
Preview without the slides menu bar, get the share URL and change the URL from /edit?usp=sharing to this /preview?rm=minimal . In this mode all changes you make to your slide or presentation will automatically be changed with everybody the URL is shared with, you do not have to resend anything. THIS IS THE METHOD I RECOMMEND FOR SHARING IF YOU DO NOT WANT TO MAKE YOUR CLASSROOM INTO A PUBLIC WEBSITE (see post #5 in the series)!
Pro Tip: If you hide/skip the extra slides your presentation and you do not want others to see, they will not be easily accessible in this share method.