How many domains are required, and why?

This partial Network diagram was provided to a QRadar deployment professional who is trying to determine if the deployment requires the definition of multiple domains.

How many domains are required, and why?
A . Three domains are required, one for each network: HR-A, HR-B, and FIN.
B . At least two domains are required to handle overlapping address spaces for the HR-B and FIN networks.
C . Three domains are required: one for each of the event processors, plus the default domain for the console.
D . No domains are required, but they might be useful to separate stored events and flows between the HR and Finance teams.

Answer: B