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 female presented with lacy linear lesions on buccal mucosa since a month with elongation of nail fold beyond the nail bed. What is the diagnosis - 
Select and explain. 
A. Psoriasis, B. Geographic tongue, C. Lichen planus, D. Candidiasis
C: Lichen planus
Answer: C: Lichen planus 
Explanation: As per the clinical picture, features such as forward growth of nail fold beyond nailbed ( pterygium) and lacy linear lesions on tongue points towards lichen planus. LICHEN PLANUS:-Inflammatory T cell mediated auto immune disorder affecting skin, hair,nails and mucous membranes.Four Ps- purple , polygonal and pruritic papule. Nail finding:-thinning , longitudinal ridging, and distal splitting of nail plate. Pterygium/ forward growth of the proximal nailfold with adherence to the proximal nail plate is a classic sign. Mucosal lichen planus:-Reticular pattern.- Lacy white pattern on buccal mucosa- whitish streaks IADVL textbook of dermatology page 1074