Which ports must be left open if an administrator plans to perform Dynamic LPAR operations?()
A、 port 21(ftp):tcp and port 657(rmc):tcp
B、 port 22(ssh):tcp and port 657(rmc):udp
C、 port 657(rmc):tcp and port 657(rmc):udp
D、 port 161(snmp):tcp and port 161(snmp):udp