According to the information presented in the following exhibit， can you tell me the reason that thetrust state of interface FastEthernet 0/3 displays "not trusted"？（）

• A、The command mis qos needs to be turned on in global configuration mode
• B、DSCP map needs to be configured for VOIP
• C、ToS has not been configured
• D、There is not a Cisco Phone attached to the interface