In a Spanning Tree Protocol (STP) environment, the port priority determines which port should be put in forwarding state when there is a tie in the path cost to the root bridge. The default port priority value is 128, and it can be adjusted to influence which port becomes the designated or root port. The lower the port priority value, the more likely the port will be selected as the designated port.
In the scenario provided, all switches are configured with the default port priority value. To ensure that traffic from PC1 is forwarded over the Gi1/3 trunk port between DWS1 and DSW2, we need to select the appropriate interface on both switches. The commands B and D are correctbecause they select the interface Gi1/3 on DSW2 and DSW1, respectively. Once the correct interface is selected, other spanning-tree related commands can be applied to influence the STP process.
The other options, A, C, and E, involve changing the port priority value, which is not necessary if the default values are already causing the desired behavior. Moreover, option C suggests setting the port priority to 0, which is not a valid value as the lowest possible priority value is 1.