If you are using an up-to-date light microscope to examine animal cells, you won't be able to detect (A)bacterial-size cell bodies
(B) the cell nucleus
(c) ribosomes
(d) cell membranes

You won't be able to detect anything smaller than the wavelength of the light you're using.

Look up the wavelength range of visible light, then look up the sizes of these components and see how they compare.