If a switch port receives a new frame while it is actively transmitting a previous frame, how does it process the frames?

If a switch port receives a new frame while it is actively transmitting a previous frame, how does it process the frames?

A. The new frame is delivered first, the previous frame is dropped, and a retransmission request is sent B. The previous frame is delivered, the new frame is dropped, and a retransmission request is sent C. The new frame is placed in a queue for transmission after the previous frame D. The two frames are processed and delivered at the same time