Host A and Host B are connected to the same switch, and Host A sends a message to Host B. When the switch starts receiving the bits, it reads the destination MAC address, determines the port Host B is...

Host A and Host B are connected to the same switch, and Host A sends a message to Host B. When the switch starts receiving the bits, it reads the destination MAC address, determines the port Host B is on, and immediately opens a channel to that port while bits are still being received. Which switch mode is being used?

A. Cut through

B. Store and forward

C. Fragment free

D. Full duplex