Final answer:
Most bacteria are viewed using a light microscope, which often requires special stains to distinguish transparent cell components. For thick structures like biofilms, a confocal scanning laser microscope is used. The correct option is B.
Step-by-step explanation:
Most bacteria are commonly viewed using a light microscope. This type of microscope uses visible light that is passed through a lens system to help the user see the specimen.
However, since individual cells are generally transparent, their components aren't distinguishable unless they're colored with special stains. Staining generally kills the cells, but it is essential to increase contrast and distinguish the microorganism against the background.
To view thick structures such as biofilms, a confocal scanning laser microscope is especially useful because it can scan multiple depth levels to create a high-resolution three-dimensional image. Special fluorescent stains are often used in conjunction with confocal microscopes to increase contrast and resolution.