What technique is Shauna using here?

Shauna is the Senior Security Analyst for the Department of Defense, in charge of all aspects of the DoD’s internal network security.As one would expect, the DoD is constantly probed and scanned by outside IP addresses, trying to find an entry into the network.Shauna leads a large team of junior security analysts that make sure all entry points are closed off, unless that entry point must be kept open for business purposes.If something must be kept open, Shauna and her employees’ duty is to make sure that hole is not exploited by outside attackers.
One way that this is accomplished, is to not use traditional ports for normally used services.All employees and outside contractors that must obtain remote access for work, are notified of the non-standard ports, and thus are able to gain access.The traditional ports used for services like http are actually kept open, but they are redirected to a secure logical area and logged.These logs enable Shauna and her team to analyze who is trying to obtain unauthorized access, and prosecute if necessary.
What technique is Shauna using here?

A.
Honeypot

B.
Firewalking

C.
Tunneling

D.
Obfuscation