The AI agrees with the suggested answer.
The recommended answer is A.
Reasoning: The question emphasizes avoiding downtime in the data plane during OMP peer connectivity loss. Option A configures OMP graceful restart, which is specifically designed to maintain data plane forwarding during control plane disruptions like vSmart controller outages. When OMP graceful restart is enabled, vEdge routers retain the last known good forwarding information received from vSmart controllers, allowing them to continue forwarding traffic even if the connection to the OMP peers (vSmart controllers) is temporarily lost.
Why other options are not the best choice:

Options B, C, and D do not configure graceful restart. While they might address other aspects of network resilience, they don't directly address the requirement of maintaining data plane forwarding during OMP connectivity loss. Without graceful restart, the data plane would be affected if the vSmart controllers become unavailable.

The configuration shown in Option A enables graceful restart which is crucial for ensuring continuous data plane operation during control plane outages.

Detailed Explanation:
Graceful restart is a mechanism that allows network devices to continue forwarding traffic even when the control plane is disrupted. In the context of Cisco SD-WAN (Viptela), this means that vEdge routers can continue forwarding data traffic even if they lose connectivity to the vSmart controllers (OMP peers). This is achieved by the vEdge routers retaining the last known good forwarding information received from the vSmart controllers and using it to continue forwarding traffic until the control plane is restored.

The configuration in Option A enables graceful restart on the vEdge router. This ensures that the router can continue forwarding traffic even if it loses connectivity to the vSmart controllers.

Without graceful restart, the vEdge routers would lose their forwarding information when they lose connectivity to the vSmart controllers, which would result in traffic disruption.

Therefore, the configuration in Option A is the only one that meets the requirement of avoiding downtime at the remote sites and data plane if the branch router loses connectivity to its OMP peers.

The key is to configure the graceful restart option, as shown in Option A, which allows vEdge routers to maintain their forwarding tables even when disconnected from the vSmart controllers.

It's also important to note that graceful restart does not prevent all disruptions. If the control plane outage is prolonged, the forwarding information on the vEdge routers may become stale, which can lead to suboptimal routing or even traffic loss. However, graceful restart can significantly reduce the impact of control plane outages and improve the overall availability of the network.

In summary, Option A is the most suitable configuration to meet the stated requirements by implementing graceful restart and ensuring the data plane remains operational despite control plane disruptions.

The below citations explain about the graceful restart and its function in Cisco SD-WAN(Viptela) network.

Cisco SD-WAN Configuration, https://www.cisco.com/c/en/us/td/docs/solutions/CVD/SDWAN/cisco-sdwan-design-guide.html
Cisco SD-WAN Graceful Restart, https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/sdwan-xe-gs-book/m-system-wide-config.html#Cisco_Reference_Topic.dita_01d85972-8a85-4997-9100-8c84e2a26d95