Answer:The number assigned to a case when it is first entered in a cancer registry is typically called the "accession number". Therefore, option A is the correct answer.
Explanation:The accession number is a unique identifier assigned to each cancer case that is recorded in a cancer registry. It is used to track the case throughout the entire cancer care continuum, including diagnosis, treatment, and follow-up. The accession number is typically generated by the cancer registry software and is based on a combination of factors, such as the date of diagnosis, the facility where the diagnosis was made, and the patient's demographic information.