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: Skin
A giant congenital melanocytic nevus is usually of the size: 
Select and explain. 
A. 5-10cm, B. 10-15 cm, C. 15-20 cm, D. >20cm
D: >20cm
Answer: D: >20cm 
Explanation: American National Institutes of Health (NIH) consensus definition to categorize naevi as small under 1.5 cm in diameter, large as having a diameter between 1.5 and 20 cm and giant naevi as having a diameter of 20 cm or more. Note: It is also called garment or bathing-trunk naevus. Most common site is lower back. Ref: Rook's textbook of dermatology, Edition-8, Page 54.10.