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
Margin of normal tissue margin taken in excision of melanoma 
Select and explain. 
A. 2cm, B. 3cm, C. 4cm, D. 5cm
A: 2cm
Answer: A: 2cm 
Explanation: For in situ melanoma a wide excision of 5 mm is sufficient; for melanoma <1 mm deep, a 1 cm margin is sufficient; and for deeper lesions, a 2 cm only margin is recommended, as there is no evidence that wider margins make a difference.Ref: Bailey and Love, 27e, page: 611