单选题In IS-IS， how does the restarting router inform its helpers that a restarts event occurred？（）A Sending out a graceful restart PDUB Sending an LSP that contains no TLVs.C Sending out a restarts TLV with the RR bit set.D Reflooding its LSP with a maximum
题目
单选题
In IS-IS， how does the restarting router inform its helpers that a restarts event occurred？（）
A
Sending out a graceful restart PDU
B
Sending an LSP that contains no TLVs.
C
Sending out a restarts TLV with the RR bit set.
D
Reflooding its LSP with a maximum sequence number.