A pathogen has been subjected to a gram stain and appears as purple clusters of round cells. which of the following species could the pathogen possibly be?
a. Escherichia coli (Gram negative bacillus)
b. Bordetella pertussis (Gram negative cocci)
c. Streptococcus pyogenes (Gram positive)
d. Staphylococcus aureus (Gram positive)
