In which access mode has this NAS been configured to operate?

At a certain customer’s site, a NAS is logically in the traffic path but not physically in the traffic path.
The NAS identifies clients by their IP addresses. In which access mode has this NAS been configured to operate?

A.
Layer 2 Edge mode

B.
Layer 2 Central mode

C.
Layer 2 In-Band mode

D.
Layer 3 mode