針對你的回答，我有不同意見，PDCP是對關聯了SRB的PDCP實體進行完整性保護，被完整性保護的數據單元包括加密前的PDU頭和數據部分。協(xié)議原文如下：

The integrity protection function includes both integrity protection and integrity verification and is performed in PDCP for PDCP entities associated with SRBs. The data unit that is integrity protected is the PDU header and the data part of the PDU before ciphering.

-integrity protection and integrity verification of control plane data;
-for RNs, integrity protection and integrity verification of user plane data;

因此，我認為，只要有關聯SRB的PDCP實體，就有完整性保護，建立SRB就是RRC層的行為，SRB2才包括NAS層的行為，而NAS是非接入層，自然不會有PDCP實體，因此C肯定錯。

最后，我不明白你說的SRB0不進行完整性保護是如何得出的。還望指教，謝謝！