Which answer do I choose?

The double integral of a function x, y) over a region R on the my plane can be expressed as an iterate integral like [L :mm = f: [0 \" HM \"manly. What is the shape of the region R? A. A unit disk centred at the origin (0,0) B. A unit disk centred at (0,1) C. A unit disk centred at (1,0) D. A halfdisk of unit radius centred at (0,1) E. A halfdisk of unit radius centred at (1,0)