The correct answers are C. Vendor OUI and D. Network traffic .

The study guide explicitly separates active/direct profiling methods from passive/non-direct methods and states that “In OT environments, passive methods are preferred over active methods.” It then lists the methods that do not require FortiNAC to interact directly with the device being profiled. Among those methods are “Network traffic: gathered from the infrastructure” and “Vendor OUI: determined by the MAC address gathered from the infrastructure.” That directly matches options C and D .

Options A and B are incorrect because SSH and SNMP are shown in the guide under the direct/active profiling methods. The guide’s point is that passive detection avoids directly scanning or interacting with OT endpoints, since that can negatively affect performance in industrial environments. Because the question specifically asks for passive detection methods, the correct pair is Vendor OUI and Network traffic .