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: Pathology
All are diseases of skin except 
Select and explain. 
A. Erythema multiforme, B. Keratosis folticularis, C. Erythema migrans, D. Psoriasis form lesion
C: Erythema migrans
Answer: C: Erythema migrans 
Explanation: Option 'C' erythema migrans is other name of ectopic geographic tongue / annulus migrans in which lesions are not always restricted to the tongue, and similar irregular or circinate lesions occurring elsewhere in the oral cavity.