Which of the following is the definition of intrusion prevention system (IPS)?

		A network hardware device or software that detects unusual network activity that might represent an intrusion, and takes action to stop the attack
		A combination of security controls that defines and implements a policy that describes the requirements to access your network
		A network hardware device or software that detects unusual activity that might represent an intrusion, and sends an alert
		A network mechanism that adds a simple label to each network packet, making routing of the packet faster than routing based on data in the header portion of the packet