I) Bacteria – At 1000x magnification we will be able to see 0.180mm, or 180 microns. Bacteria are too small to see without the aid of a microscope. While some eukaryotes, such as protozoa, algae and yeast, can be seen at magnifications of 200X-400X, most bacteria can only be seen with 1000X magnification.
Bacteria cells have ribosomes and a cell wall, but they don't have organelles such as nuclei, mitochondria or chloroplasts. Bacteria cells do have a cytoplasm and cell membrane. One of the key structures of a bacteria cell is the plasmid.
II) Plant cell – Using a light microscope of 100X magnification power, we can view cell walls, vacuoles, cytoplasm, chloroplasts, nucleus and cell membrane of plant cell.
Plant cells have a cytoplasm, cell membrane, mitochondria and nucleus which all perform the same functions as animal cells.
III) Ribosome - A ribosome is a cell organelle which can be seen only through electron microscope and cannot be seen with a light microscope. It functions as a micro-machine for making proteins. Ribosomes are found ‘free’ in the cytoplasm or bound to the membrane system i.e., the endoplasmic reticulum (ER) to form rough ER.
IV) Virus – Viruses are very small and most of them can be seen only by electron microscopy. A virus is a small collection of genetic code, either DNA or RNA, surrounded by a protein coat. A virus cannot replicate alone. Viruses must infect cells and use components of the host cell to make copies of themselves. Often, they kill the host cell in the process and cause damage to the host organism.
Hence, option (c) is correct.