Ellipse --> What relation represents the shaded region if the vertices integ coordina

I am given an ellipse graph with a major of axis that is 6 units wide and a minor axis 4 units wide. (represented graphically and I made it into words)

The question asks:

"What relation represents the shaded region if the vertices have integral coordinates?"

I do not understand what integral coordinates means and what the question is asking in the first place.

Any help would be greatly appreciated!

Thanks in advance!