Final answer:
A Network Security Group (NSG) allows or denies inbound network traffic to your Azure resources by acting as a virtual firewall.
Step-by-step explanation:
The correct answer is C) Network security group.
A Network Security Group (NSG) is a virtual firewall that controls inbound and outbound traffic to Azure resources. It acts as a filter, allowing or denying network traffic based on rules and policies that you define.
For example, you can create a rule in an NSG that allows inbound traffic to a specific port on a virtual machine, while denying inbound traffic to other ports. This helps to secure your Azure resources and control the flow of network traffic.