Refer to the exhibit.

 MPLS LDP (Label Distribution Protocol) is used for label distribution in MPLS networks. When making changes to the LDP configuration, it’s essential to ensure that the changes do not disrupt existing LDP sessions. In this scenario, the network administrator implemented MPLS LDP changes on the PE-A LSR (Label Switching Router) device, and the goal is to prevent any disruption to LDP peers.

The MPLS LDP Non-Stop Routing (NSR) feature allows LDP sessions to survive control-plane switchover events without interruption. When NSR is enabled, the LDP session state information is synchronized between the active and standby control planes. If the active control plane fails, the standby control plane takes over seamlessly, and LDP sessions continue without interruption.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/msp/configuration/xe-3s/mp-ha-xe-3s-book/mp-nsr-ldp-supp.pdf