VirtualBox has no Guest Additions option in the Machine menu

[eiger3970]

Hi,
I've been trying to make my guest vm have a full screen.
Downloaded the guest additions.
No guest additions in VirtualBox > Machine?

I can maximize the screen of the guest VM, but the screen is all grainy.
Before I reinstalled the guest VM, the full screen worked nicely with a little VirtualBox taskbar at the bottom which was hidden and appeared only when I moved the mouse arrow near the bottom.

Please help.