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: Dental
A 28-year-old patient has multiple grouped papulovesicular lesions on both elbows, knees buttocks and upper back associated with severe itching. The most likely diagnosis is – 
Select and explain. 
A. Pemphigus vulgaris, B. Bullous pemphigoid, C. Dermatitis herpetiformis, D. Herpes Zoster
C: Dermatitis herpetiformis
Answer: C: Dermatitis herpetiformis 
Explanation: Look for itching → Severe itching
Papulovesicular lesion
On extensors (knees, elbows), scapular region (upper back), buttock.
Age → 28 years