Which Statements About BGP Route Advertisement Are True? (Choose Two

Which statements about BGP route advertisement are true? (Choose two.)

A) All BGP routes learned from BGP peers are advertised to other BGP peers.
B) Only the routes learned from an IGP are advertised to other BGP peers.
C) By default, the routes learned from IBGP peers are not advertised to other IBGP peers.
D) Only the optimal routes are advertised to other BGP peers.