A Student Suggests That Prokaryotic and Eukaryotic Cells Must Be $\mu$

A student suggests that prokaryotic and eukaryotic cells must be about the same size since both types of cells can be observed using a light microscope.Which statement provides the best response to this suggestion?

A) The suggestion is reasonable because all cells are much smaller than 200 $\mu$ m, which is the size of the smallest object that a human can see without aid.
B) The suggestion is reasonable because all cells have an upper limit on size that results from limitations to molecular movement in and out of the cell.
C) The suggestion is reasonable because prokaryotic and eukaryotic cells share the same fundamental structure of an internal cytoplasm surrounded by a cell membrane.
D) The suggestion is not reasonable because eukaryotic cells are found in both unicellular and multicellular organisms, whereas all prokaryotes are unicellular.
E) The suggestion is not reasonable because light microscopes can allow a wide range of cell sizes to be seen.