This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
Chronic Burrowing ulcer is caused by 
Select and explain. 
A. Microaerophilic streptococci, B. Peptostreptococcus, C. Streptococcus viridans, D. Streptococcus pyogenes
A: Microaerophilic streptococci
Answer: A: Microaerophilic streptococci 
Explanation: Microaerophilic streptococci (Burrowing ulcer / Maleny's ulcer is caused by synergistic infection of microaerophilic non hemolytic streptococci and aerobic hemolytic streptococci)