Which actions must be taken to carry voice?

Refer to the exhibit.

Refer to the exhibit. An engineer configures ISDN on a voice gateway. The provider confirms that the PRI is configured with 10 channels the engineer ordered and is working from the provider side, but the engineer cannot get a B-channel to carry voice. The rest of the configuration for the serial interface and voice network is functioning correctly. Which actions must be taken to carry voice?
A. The engineer must activate the controller card on the voice gateway before configuring the device.
B. The engineer used a T1 interface but must use an E1 interface.
C. The pri-group timeslots command must be 0-9 for the 10 channels because all values on a router start with 0.
D. The engineer must manually revert the order of using the channels.