This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
The most common organism that causes the following condition is 
Select and explain. 
A. Poly-microbial, B. beta haemolytic streptococci, C. Clostridium perfringes, D. Clostridium tetani
B: beta haemolytic streptococci
Answer: B: beta haemolytic streptococci 
Explanation: The above image is that of cellulitis of the leg.Cellulitis is a non-suppurative, invasive infection of tissues, which is usually related to the point of injury.Typically caused by B haemolytic streptococci, staphylococci and Clostridium perfringens. Streptococci being the commonest.Necrotising fasciitis is mostly polymicrobialGas gangrene is caused by Clostridium perfringens.Ref: Bailey and love 27th edition PG: 48