Concept:Bacteria are classified by their shape, and each shape has a specific scientific name.Explanation:A coccus is a bacterium that is spherical or round in shape.The plural form of coccus is cocci.Bacillus refers to rod-shaped bacteria.Vibrio refers to curved-rod-shaped bacteria.Diplobacillus refers to rod-shaped bacteria that occur in pairs linked end to end.Since the question asks for a spherically shaped bacterium, the correct term is coccus.Answer:B. coccus