Answer:
A. Network Reconnaissance.
Explanation:
Network Reconnaissance is a process of testing for vulnerability in a network. It could be a legitimate testing by a network operator to protect the network, setting acceptable user policies or a attacker finding a way to the network. In this process, intrusion detection mostly gives alarm on every reconnaissance activities.
To launch a scan in a network, an operator must have in mind to either carry out a reconnaissance activity or scan for network Reconnaissance attacks.
