With unity 2017.1, the option to select the "2D" asset pack no longer exists. When searching for the package on the web, I found that Unity removed it from the asset store.
Yes it was removed, it's included in the project files. I still have access to the asset since I downloaded it a while back, so I included it with the project files ("Unity_Sprites"). Nonetheless everything taught in the course can be used with any of the 2D assets packages Unity provides.