Which of the following tcpdump commands will display only TCP traffic going from to on standard FTP ports?
1) tcpdump -nn tcp and port 20 or port 21 and src and dst
2) tcpdump -nn tcp and port 20 or port 21 and src or dst
3) tcpdump -nn udp and port 20 or port 21 and src and dst
4) tcpdump -nn tcp and port 20 and port 21 and src and dst