This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Aerial disorders, Subject name: Surgery
Which ulcer is likely to develop in a long standing chronic venous ulcer? 
Select and explain. 
A. Marjolin ulcer, B. Apthous ulcer, C. Bazin ulcer, D. Aerial ulcer
A: Marjolin ulcer
Answer: A: Marjolin ulcer 
Explanation: - Marjolin's ulcer: Arises from long standing ulcer or burn scar Is a low-grade squamous cell carcinoma Destruction of - Nerves - painless - Vessels - slow growth, radio resistant, no distant metastasis - Lymphatics - no lymph node metastasis - Diagnosis by biopsy - Treated by wide local excision with flap closure