In a Huawei base station, which of the following bearers can only be configured as...

 According to the LTE-NR tight-interworking and the first steps to 5G, in a Huawei base station, QCI2 can only be configured as an MCG (Master Cell Group) bearer. QCI2 is a voice bearer that requires low latency and high reliability. Therefore, it cannot be configured as an SCG (Secondary Cell Group) bearer or a split bearer that may introduce additional delay or packet loss. QCI6, QCI9, and QQ1 can be configured as either MCG bearers, SCG bearers, or split bearers depending on the service requirements and network conditions.