Final answer:
Yes, you can associate a network security group to a virtual network subnet.
Step-by-step explanation:
True. You can associate a network security group to a virtual network subnet. A network security group is a container for a set of security rules that allow or deny inbound or outbound network traffic based on protocol, port, and source/destination IP addresses. By associating a network security group to a virtual network subnet, you can control the network traffic flow to and from the resources within that subnet.