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: Dental
Mycobacterium causing skin ulcer – a) M. smegmatisb) M. scrofulaceumc) M. ulceransd) M. fortuitume) M. marinum 
Select and explain. 
A. abd, B. acd, C. bde, D. cde
D: cde
Answer: D: cde 
Explanation: Mycobacteria causing skin infections

Post-trauma abscess → M.chelonae, M.fortuitum, M.terrae
Swimming pool granuloma → M.marinum(M. Balanei)
Buruli ulcer → M.ulcerans
Lupus vulgaris → M.tuberculosis
Scrofuloderma → M.tuberculosis 
Abscess and granuloma may break to fonn an ulcer.
So, all the organism in above list can cause skin ulcer.