This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Papulosquamous disorders, Subject name: Dental
A young lady present with white lacy lesions in oral cavity and her proximal nail fold has extended onto the nail bed. What is the likely diagnosis - 
Select and explain. 
A. Psoriasis, B. Geographic tongue, C. Lichen planus, D. Candidiasis
C: Lichen planus
Answer: C: Lichen planus 
Explanation: In lichen planus there is mucosal involvement - White, reticulated, Lacey pattern on the buccal mucosal, tongue and gingiva. Nail changes include thinning of nail plate, trachyonychia (same paper nails) , tenting of nail plates(pup tent sign) and pterygium( proximal nail fold is prolonged on to the nail bed , splitting and destroying nail plate. IADVL textbook of dermatology , page 1070