A TCP connection is in progress. The receiver needs some time to process some data it has received, so it sends an ACK segment to the transmitter with window size=O. The transmitter receives the ACK and stops transmitting. Some time later, the receiver sends another ACK with window-size=2, but this segment is lost by the IP layer. What happens next? The connection will timeout and the data transfer will have to start all over again The keepalive timer will expire and the transmitter will begin sending again The persistence timer in the transmitter will expire and it will send a PROBE segment to the receiver to effectively request for the retransmission of the lost ACK. The persistence timer in the receiver will expire and the ACK will automatically be resent Karn's algorithm will ensure that the ACK is re-sent almost immediately