The top SD-WAN benefits are:
+ Increased bandwidth at a lower cost
+ Centralized management across branch networks
+ Full visibility into the network
+ Providing organizations with more connection type options and vendor selection when building a network.
Reference:
-> We can provision endpoints (vEdges) through a centralized router vManage -> Answer D is correct.
Answer A is not correct as we can use different kind of connections on SD-WAN: MPLS, LTE, 4G, xDSL, Internet
connections...
Application-Aware Routing policy is configured in vManage as a centralized data policy that maps the service-
side application(s) to specific SLA requirements. The centralized policies provisioned in vSmart controller is pushed
to relevant WAN Edge devices for enforcement. The defined policy consists of match-action pairs, where the match
statement defines the application-list or the type of traffic to match, and the action statement defines the SLA
action the WAN Edge devices must enforce for the specified traffic.

Explanation

+ accepts LISP encapsulated map requests: LISP map resolver
+ learns of EID prefix mapping entries from an ETR: LISP map server
+ receives traffic from LISP sites and sends it to non-LISP sites: LISP proxy ETR
+ receives packets from site-facing interfaces: LISP ITR
Explanation
ITR is the function that maps the destination EID to a destination RLOC and then encapsulates the original packet with an additional header that has the source IP address of the ITR RLOC and the destination IP address of the RLOC of an Egress Tunnel Router (ETR).
After the encapsulation, the original packet become a LISP packet.
ETR is the function that receives LISP encapsulated packets, decapsulates them and forwards to its local EIDs. This function also requires EID-to-RLOC mappings so we need to point out an "map-server" IP address and the key (password) for authentication.
A LISP proxy ETR (PETR) implements ETR functions on behalf of non-LISP sites. A PETR is typically used when a LISP site needs to send traffic to non-LISP sites but the LISP site is connected through a service provider that does not accept no routable EIDs as packet sources. PETRs act just like ETRs but for EIDs that send traffic to destinations at non-LISP sites.
Map Server (MS) processes the registration of authentication keys and EID-to-RLOC mappings. ETRs sends periodic Map-Register messages to all its configured Map Servers.
Map Resolver (MR): a LISP component which accepts LISP Encapsulated Map Requests, typically from an ITR, quickly determines whether or not the destination IP address is part of the EID namespace

EIGRP maintains alternative loop-free backup via the feasible successors. To qualify as a feasible successor, a router must have an Advertised Distance (AD) less than the Feasible distance (FD) of the current successor route.
Advertised distance (AD): the cost from the neighbor to the destination. Feasible distance (FD): The sum of the AD plus the cost between the local router and the next-hop router