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
60 year female with tense bulla in lower extremity and subepidermal bullous lesion on microscopy, diagnosis is? 
Select and explain. 
A. Bullous pemphigoid, B. Pemphigus vulgaris, C. Erythema multiforme, D. Dermatitis herpetiformis
A: Bullous pemphigoid
Answer: A: Bullous pemphigoid 
Explanation: Ans. is 'a' i.e., Bullous pemphgoid See explanation- 1 of session- 10 of Skin of All India 2014-15 pattern of this book.