What is split horizon?

[A].	Information about a route should not be sent back in the direction from which the original update came.
[B].	It splits the traffic when you have a large bus (horizon) physical network.
[C].	It holds the regular updates from broadcasting to a downed link.
[D].	It prevents regular update messages from reinstating a route that has gone down.

Answer: Option A

Explanation:

A split horizon will not advertise a route back to the same router it learned the route from.