下面属于5G NR下行链路reference signal的是()

下面属于5G NR下行链路reference signal的是()

A. Demodulation reference signals for PDSCH

B) Phase-tracking reference signals for PDSCH

C) Demodulation reference signals for PDCCH

D) Demodulation reference signals for PBCH

E) CSI reference signals

此题为多项选择题。请帮忙给出正确答案和分析，谢谢！