An administrator tries to change the checksum_offload setting on ent0, but the chdev command responds that the adapter is busy.  What can be done to resolve this()?  
A、Use chdev with -P flag and run cfgmgr.
B、Use chdev with -R flag and run cfgmgr.
C、Use chdev with -P flag and reboot the system.
D、Use chdev with -R flag and reboot the system.