The system administrator notices that after running netstat -rn， several small c’s are showing up under the flags columns， and routes that were not defined are also showing up. How can these cloned routes be stopped？（）

A、 By default cloned routes are turned on.  To turn cloned routes off issue the command：      #no -o tcp_pmtu_discover=0       #no -o udp_pmtu_discover=0       and add to the rc.net or rc.bsdnet file for next reboot

B、 By default cloned routes are turned on.  To turn cloned routes off issue the command：        # no -o tcp_pmtu_discover=1        #no -o udp_pmtu_discover=1         and add to the rc.net or rc.bsdnet file for next reboot

C、 By default cloned routes are turned on.  To turn cloned routes off issue the command：         #no -o ipforwarding=0         and add to the rc.net or rc.bsdnet file for next reboot

D、 By default cloned routes are turned on.  To turn cloned routes off issue the command：         #no -o ipforwarding=1         and add to the rc.net or rc.bsdnet file for next reboot