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
Phrynoderma is a cutaneous manifest-ation of severe deficiency of vitamin : 
Select and explain. 
A. A, B. B, C. C, D. D
A: A
Answer: A: A 
Explanation: A i.e. A