Final answer:
Case registries are used to track patients with specific diseases and to select cases in case-control studies. They are not small sets of information related to specific patients in a study. Therefore, the correct option is B.
Step-by-step explanation:
One of the major applications of case registries is to track patients with specific diseases, such as cancer. This helps researchers and healthcare providers gather data on the occurrence, characteristics, and outcomes of these diseases.
Another major application of case registries is to select cases in case-control studies. Case-control studies compare a group of subjects with a specific disease (cases) with a group of similar subjects without the disease (controls) to identify risk factors and potential causes.
Therefore, the answer is b. Case registries are small sets of information related to specific patients in a study. Case registries are not a major application of case registries. Instead, case registries serve as a data collection tool for research and healthcare purposes.