___ bacteria form in clusters.
A. Streptococci
B. Clostridium difficile
C. Staphylococci
D. Diplococci
C. Staphylococci
To determine the bacteria that form in clusters, we can analyze the options provided and identify the correct answer through process of elimination.
A. Streptococci: Streptococci bacteria commonly occur in chains, not clusters, so option A can be eliminated.
B. Clostridium difficile: Clostridium difficile bacteria usually do not form clusters, but instead occur as individual cells or in small groups. Therefore, option B can be eliminated.
C. Staphylococci: Staphylococci bacteria are known for their characteristic cluster formation, where they arrange in irregular grape-like clusters. This is the correct option for bacteria that form in clusters, so option C is the answer.
D. Diplococci: Diplococci bacteria form pairs, not clusters. Therefore, option D can be eliminated.
In conclusion, the bacteria that form in clusters are Staphylococci, which makes option C the correct answer.