Refer to the exhibit.  Why does the trust state of interface FastEthernet 0/3 show "not trusted"？  （）

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