What Is Routing Protocol Convergence Time Defined As

What is routing protocol convergence time defined as?

A) It is the time it takes for the protocol to recognize the best path in the event of a network change.
B) It is the time it takes for the protocol to recognize that a change has occurred.
C) It is the amount of time it takes after initial configuration of the protocol for all routes to become known.
D) It is the amount of time involved in configuration of the routing protocol.