What happens if all CTI ports for the configured CTI Port Group are busy when a new call arrives?

What happens if all CTI ports for the configured CTI Port Group are busy when a new call arrives?

A.
CallManager will forward the call to the directory number configured for forward-on busy for this CTI Route Point in CallManager.

B.
Caller will receive ringing treatment.

C.
An exception is raised, but the call is accepted and processed.

D.
Caller will receive network busy treatment.

E.
CallManager will forward the caller to the directory number configured in IPCC Express for overflow.