What is the different between a CPU with or without the GPU?

This may be a dumb question. But this is definitely a quick n easy question for those who know it :)

When I choose to buy a CPU with No GPU, such as some of the Intel Xeon CPUs, what should I bear in mind?

To be specific, here are some cases:

(A) - CPU without GPU
    - NO on-board graphics
    - NO graphic cards

Will I able to display? (poor graphic though.)

(B) - CPU without GPU
    - on-board graphics
    - NO graphic cards

Graphic quality depends on the on-board chips, right?

(C) - CPU without GPU
    - NO on-board graphics
    - graphic card

Graphic quality depends on the graphic card, right? (I am quite sure to this one)

Solution 1:

Case A: There will be no graphics output. You can still connect a keyboard and mouse, but you won't be able to display anything

Case B: You will be able to output video through your CPU, this is usually only good enough for excel/word/watching movies. Not recommended for gaming, rendering video, etc

Case C: You will be able to output video through your graphics card. What you are able to do with it depends on the card you buy.