Final answer:
The results of a case study are not generally applicable.
Step-by-step explanation:
The correct answer is b. Its results are not generally applicable.
A case study is a research method that involves in-depth investigation and analysis of a specific individual, group, or situation. While it provides in-depth and detailed information about the subject of study, the results of a case study are not generally applicable to a larger population. Therefore, option b is the best description of the results of a case study.