This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Catalase positive, beta-hemolytic staphylococcus - 
Select and explain. 
A. S. aureus, B. S. epidermidis, C. S. saprophyticus, D. None
A: S. aureus
Answer: A: S. aureus 
Explanation: All staphylococci are catalase positive.
Amongst staphylococci, staph. aureus is beta-hemolytic.
Most species of coagulase-negative staphylococcus species are non-hemolytic.