This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Photosensitive disorders, Subject name: Dental
Which of the following ultra-violet radiation cause most skin disorder- 
Select and explain. 
A. UV-A, B. UV-B, C. UV-C, D. None
B: UV-B
Answer: B: UV-B 
Explanation: Cutaneous responses to uv radiation UVA -315-400nm immediate erythema Immediate pigment darkening- merowsky phenomenon drug induced photosensitivity photoageing UVB- 280-315nm 1000x more erythmogenic, associated with sunburn delayed melanogenogenesis major role in carcinogenesis role in photoageing role in vitamin d synthesis UVB has more damage to skin fitzpatrick textbook of dermatology page 267