A: You can classify columns manually, as an alternative or in addition to the recommendation-based classification:

* Select Add classification in the top menu of the pane.
* In the context window that opens, select the schema, table, and column that you want to classify, and the information type and sensitivity label.
* Select Add classification at the bottom of the context window.
C: An important aspect of the information-protection paradigm is the ability to monitor access to sensitive data. Azure SQL Auditing has been enhanced to include a new field in the audit log called data_sensitivity_information. This field logs the sensitivity classifications (labels) of the data that was returned by a query. Here's an example:

Reference:
https://docs.microsoft.com/en-us/azure/azure-sql/database/data-discovery-and-classification-overview