Which of the following best describes distance vector protocols?

They periodically exchange copies of routing tables between adjacent routers and do not maintain any knowledge of links on non adjacent routers.

They use shortest path first algorithms, do not exchange copies of routing tables between routers and do maintain knowledge of links on non adjacent routers.

They periodically exchange copies of routing tables between adjacent routers and maintain knowledge of links on non adjacent routers.

They use shortest path first algorithms, exchange copies of routing tables between routers and maintain knowledge of links on non adjacent routers.