Which of the following statements regarding ISDN are correct?（）
- A Each ISDN B channel has transmission speeds of up to 64 kbps.
- B The ISDN B channel can carry video, voice or data.
- C The ISDN B channel transmission rate varies depending on the service used.
- D The ISDN D channel transmits control information.
- E The ISDN B channels can be configured with different subnets and encapsulation types when dialer profiles are configured.