B

Herpes simplex recurrences characteristically appear at fixed, keratinised oral sites such as the vermilion border, hard palate and attached gingiva—i.e., they show clear site-specificity—whereas syphilitic chancres, traumatic aphthae and carcinomas can arise at many different oral locations [Eisen, 1998, PMID 9798227; Woo, 1997, PMID 9117756].