单项选择题
A.firewall-cmd-query-port=80/tcpB.firewall-cmd-add-port=80/tcpC.systemctl enable httpd.serviceD.systemctl is-enabled httpd.servie
A.bindB.nfs-utilsC.nfs-serverD.nfs
A.大于封头内直径B.等于封头内直径C.没有关系