Refer to the exhibit.

When adding a FortiGate device to FortiManager using the discovery process, and FortiManager is operating behind a NAT device, configuring the FortiManager's NATed IP address in the system administration settings of FortiManager is crucial. This setup ensures that the FortiGate device can communicate with the FortiManager through the NAT device. By providing the NATed IP address of FortiManager, you're essentially telling the FortiGate where to send its management traffic so that it can be properly routed through the NAT device to reach the FortiManager. The process does not involve setting the NAT device's IP address on the FortiGate; instead, it utilizes the configured NATed IP address of the FortiManager to establish the management connection. This makes option B the expected result of this configuration scenario.