Which three trust states and boundary design principles are correct? $($Choose three.$)$

The trust boundary should be close to the destination of the traffic.

The trust boundary should be close to the source of the traffic.

When a switch port is configured in the untrusted state, the port discards any Layer $2$ and Layer $3$ markings and sets a DSCP value of $0$ for the packet.

When a switch port is configured in the untrusted state, the port accepts any Layer $2$ and Layer $3$ markings and sets a DSCP value according to the predefined CoS$-$to$-$DSCP mapping.

When a switch port is configured to trust the CoS state, the port accepts CoS markings and calculates an internal DSCP value according to the predefined CoS$-$to$-$DSCP mapping.

When a switch port is configured to trust the DSCP state, the port accepts the DSCP marking and sets the DSCP value of $0$ for the IP packet.