Final answer:
The ICD-9 code for extragenital durum ulcus is 099.0, which categorizes diseases and related health problems, specifically referencing a hard ulcer outside the genital area.
Step-by-step explanation:
The code that indicates extragenital durum ulcus is b.) 099.0. This is a classification found within the International Classification of Diseases, Ninth Revision (ICD-9), which is used to code and categorize diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases. In the context of extragenital durum ulcus, which is not commonly encountered in standard medical terminology, it may refer to a hard (durum) ulcer located outside the genital area (extragenital).