Melissa is implementing the incremental data load from multiple on-premises SQL server tables to Azure SQL tables using Azure Data Factory. She is performing the incremental data copy by delta data loading from the source database using a watermark. 
What is the functionality of the watermark in this scenario?

Answer options:

A.It represents the SQL Server connection string.
B.It’s a column that has the last updated timestamp or an incrementing key.
C.It represents the last SYS_CHANGE_VERSION
D.It represents the new SYS_CHANGE_VERSION

Correct Answer: B 

https://docs.microsoft.com/en-us/azure/data-factory/tutorial-incremental-copy-overview