Download is the Only Option for Printing a Lab

Help;

Only the option to download is available in Firefox when I try to print a lab report from inside OSCAR's inbox. How do I change the options back to Preview instead of Download?

Resolution;

This often results from accidentally checking the option that says: "Do this automatically for files like this from now on." during a previous print activity. 

To change this setting back to normal:

1.) open the Firefox menu located at the top right
2.) select Options
3.) scroll down to Applications
4.) under the Content Type column, look for Portable Document Format (PDF)
5.) from the drop down menu in the adjacent column, select Preview in Firefox