4.3.10. Network Address Translation (NAT). Which one of the following operations is NOT performed by NAT.? Select one: a. On an incoming datagram from the public internet side of a NAT, changing the destination IP address of a datagram to a new destination IP address that is looked up in the NAT table, and (possibly after other actions), sending that IP datagram on to the LAN side of the NAT b. Generating ACKs back to the TCP sender and then taking responsibility for reliably delivery the segment to its destination, possibly using a non-TCP reliable data transfer protocol c. On an outgoing datagram, changing the source IP address of a datagram received from the LAN side of the NAT d. On an outgoing datagram changing the transport-layer port number of the transport-layer segment inside a datagram received from the LAN side of the NAT.