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: Dental
A 36 year–old factory worker developed itchy, annular scaly plaques in both groins. Application of a corticosteroid ointment led to temporary relief but the plaques continued to extend at the periphery.The most likely diagnosis is – 
Select and explain. 
A. Erythema annulare centrifugum, B. Granuloma annulare, C. Annular lichen planus, D. Tinea cruiris
D: Tinea cruiris
Answer: D: Tinea cruiris 
Explanation: Tinea cruiris is dermatophytic infection of groin. Presence of bilateral, annular scaly plaques in the groin, itching and unresponsiveness to steroids and peripheral extension, all suggest the diagnosis of Tinea cruris.