A lightweight access point in which one of the following architectures participate?

(A) Light-MAC
(B) Tunnel-MAC
(C) Big-MAC
(D) Split-MAC

Split-MAC is the correct answer.

On a lightweight AP, the MAC function is divided between the AP hardware and the WLC. The LAP-WLC division of labor is known as split-MAC architecture.

The Split MAC architecture divides the implementation of the MAC functions between the AP and the controller.

The 802.11 AP at its simplest level is the 802.11 radio MAC layer providing bridging to a wired network for the WLAN client associated to the AP Basic Service Set Identifier (BSSID). The 802.11 standard extends the single AP concept to allow multiple APs to provide an extended service set (ESS), where multiple APs use the same ESS identifier (ESSID; commonly referred to as an SSID) to allow a WLAN client to connect to the same network through different APs.

The LWAPP split MAC concept breaks the APs making up the ESS into two component types: the LWAPP AP, and the WLC. These are linked via the LWAPP protocol across a network to provide the same functionality of radio services, as well as bridging of client traffic in a package that is simpler to deploy and manage than individual APs connected to a common network.
Note: Although the split MAC provides a Layer 2 connection between the WLAN clients and the wired interface of the WLC, this does not mean that the LWAPP tunnel passes all traffic; the WLC forwards only IP Ethertype and its default behavior is not to forward broadcast or multicast traffic. This becomes important when considering multicast and broadcast in the WLAN deployment.