Compared with the traditional STP, RSTP defines two different port roles. Which is correct? (Multiple choices)

Compared with the traditional STP, RSTP defines two different port roles. Which is correct? (Multiple choices)
A . The primary port is used to back up the root port, and the backup port is mainly used to back up the specified port.
B . If the designated switch of the network segment is the switch to which this port belongs, the port status is set to the standby port.
C . The backup port is in the forwarding state and the owning switch is the designated switch of the network segment to which the port is connected.
D . The standby port is in the forwarding state and the owning switch is not the designated switch of the network segment to which the port is connected.
E . Neither the backup port nor the standby port is in the forwarding state.

Answer: AE