A 30 year old male had severely itchy papula-vesicular lesions on extremities,knees,elbows and buttocks for one year.Direct immunofluorescence staining of the lesions showed IgA deposition at dermoepidermal junction.The most probable diagnosis is :

• A. Bullous pemphigoid
• B. Pemphigus vulgaris
• C. Nummular eczema
• D. Dermatitis herpetiformis