The most likely cause of the problem is that the switch port that the new PC is connected to is configured with port security, which is a feature that limits the number of MAC addresses that can be learned on a port.
Port security can prevent unauthorized devices from accessing the network by either shutting down the port or dropping the traffic from the unknown MAC address.
Since the existing PC operates normally, it means that its MAC address is already authorized on the switch port, but the new PC's MAC address is not.
Therefore, the technician should contact the network team to either disable port security on the switch port or add the new PC's MAC address to the authorized list.
This will allow the new PC to get an IP address on the client's VLAN and access the network resources.
The other options are not relevant to the situation, as they do not address the root cause of the problem.
Option B is incorrect because creating a record in DNS for the new PC will not help it get an IP address or connect to the network.
Option C is incorrect because reviewing the logs on the company's SIEM will not fix the port security issue or restore the network connectivity for the new PC.
Option D is incorrect because checking NetFlow data from the connected switch will not identify or resolve the port security issue or the network issue for the new PC.
Reference:
1: CompTIA Network+ N10-008 Study Guide, Chapter 3, Section 3.4, "Port Security", page 147-148.
2: Professor Messer's CompTIA N10-008 Network+ Course Notes, Section 3.4, "Port Security", page 30.
3: CompTIA Network+ N10-008 Study Guide, Chapter 2, Section 2.3, "DNS Concepts", page 79-80.
4: CompTIA Network+ N10-008 Study Guide, Chapter 6, Section 6.2, "SIEM", page 316-317.
5: CompTIA Network+ N10-008 Study Guide, Chapter 5, Section 5.1, "NetFlow", page 262-263.