In order to improve link reliability, the LT device configures the Time delay protection group through two uplink ports 0/19/0 and 0/20/0. Which of the following commands is optional?
A . huawei （ config ） #interface giu 0/ 19
huawei （ config-if-giu-0/19 ） h offline-tx-off-time0500
B . huawei （ protect-group-0 ） h protect-group member port 0/19/0role work
C . huawei （ protect-group-0 ） a protect-group enable
D . huawei （ config ） =protect-group 0 protect-target sth-nni port work mode time delay
Answer: A