Which statement about the VideoStream/Multicast Direct feature is true?

Which statement about the VideoStream/Multicast Direct feature is true?

A. IP multicast traffic is reliable over WLAN by default as defined by the IEEE 802.11 wireless multicast delivery mechanism. B. Each VideoStream client acknowledges receiving a video IP multicast stream. C. It converts the unicast frame to a multicast frame over the air. D. It makes the delivery of the IP multicast stream less reliable over the air, but reliable over Ethernet.