When the GR Restarter Performs the Active/standby Switchover, the Neighbor

When the GR Restarter performs the active/standby switchover, the neighbor performs which of the following operations when detecting that a TCP disconnection? (Choose three.)

A) Keeping the routing tables of various address families advertised by the GR Restarter during negotiation, marking entries in these tables with stale tags, and starting a stale timer
B) Starting a restart timer.
C) Clearing all routing entries and forwarding entries related to the GR restarter if the GR restarter fails to re-establish the BGP connection with the neighbor after the restart timer expires.
D) Remaining the neighbor relationship unchanged.