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: Pathology
The commonest type of Porphyria is 
Select and explain. 
A. Variegate porphyria, B. Porphyria cutanea tarda, C. Congenital erythropoietic porphyria, D. Acute intermittent porphyria
B: Porphyria cutanea tarda
Answer: B: Porphyria cutanea tarda 
Explanation: None