Final answer:
The invalid privacy level for a Power BI data source is 'Confidential'. In Power BI, the valid privacy levels are Public, Organizational, and Private.
Step-by-step explanation:
The question relates to the privacy levels that can be set for a data source within Power BI, a business analytics tool. In Power BI, privacy levels determine how data can be combined with other data sets. The available privacy levels are:
Public
Organizational
Private
The option Confidential is not present as a valid privacy level in Power BI. Therefore, Confidential is not a valid privacy level for a Power BI data source.