This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
RHD diagnostic criteria include 
Select and explain. 
A. Oral ulcer, B. Malar rash, C. Erythema marginatum, D. Nail telengectasia
C: Erythema marginatum
Answer: C: Erythema marginatum 
Explanation: Erythema marginatum is a cutaneous finding associated with acute rheumatic fever. The lesions typically develop 7 days to months after the onset of the streptococcal pharyngitis or, rarely, streptococcal skin infections. Erythema marginatum occurs in about 10% cases of acute rheumatic fever. Jones criteria is used for diagnosis of rheumatic fever . Its shown in the following picture Ref Davidson edition23rd pg 532