What Is the Reason That You Want to Synchronize IGP

Multiple Choice

What is the reason that you want to synchronize IGP and BGP convergence by advertising an infinite metric in OSPF or setting the overload bit in IS-IS?

A) to prevent traffic loss when the path from a router to a BGP next hop traverses another router that has not yet learned the path via BGP
B) to prevent churning between multiple available routes reachable through IGP and BGP
C) to prevent BGP from converging faster than IGP, which can cause temporary routing loops in the network
D) to prevent routes which are learned both from IGP and BGP from forming a routing loop