This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fungal infections, Subject name: Dental
A 36-yr-old male worker presented with itchy, annular, scaly diffuse plaques in both the groins. Application of coicosteroid ointment relieved the symptoms temporarily but the plaques continued to spread at the periphery. The most likely diagnosis would be? 
Select and explain. 
A. Erythema annulare centrifugum, B. Granuloma annulare, C. Annular lichen planus, D. Tinea Incognito
D: Tinea Incognito
Answer: D: Tinea Incognito 
Explanation: All of the above options are annular lesions But the clinical features: itchy annular lesion with diffuse scaly plaques at groins and relief from symptoms by use of glucocoicoids points towards Tinea Incognito. Granuloma annulare is also annular but classically non scaly. Annular lichen planus is classically on mucosal areas and not groins.