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
Mucosa is never involved in which of the following disorders – 
Select and explain. 
A. Dermatitis herpetiformis, B. Pemphigus vulgaris, C. Epidermolysis bullosa acquisita, D. Toxic epidermal necrolysis
A: Dermatitis herpetiformis
Answer: A: Dermatitis herpetiformis 
Explanation: Mucosal involvement

Common                →   Pemphigus
Rare                      →   Pemphigoid
Not involved          →   Dermatitis herpetifo