Question: Upon receiving an RRCReconfigurationCompleteSidelink message that includes the sl-DRX-ConfigReject, what action does the UE take regarding sidelink DRX for the corresponding sidelink unicast communication?
Option 1: The UE applies a default sidelink DRX configuration.
Option 2: The UE requests new sidelink DRX configurations from the network.
Option 3: The UE considers no sidelink DRX to be applied for the corresponding sidelink unicast communication.
Option 4: The UE restarts the timer T400 to await further sidelink DRX instructions.
Explanation: When an RRCReconfigurationCompleteSidelink message includes the sl-DRX-ConfigReject, it indicates that the previously requested or proposed sidelink Discontinuous Reception (DRX) configuration is not accepted. In this scenario, according to the specified behavior for such a rejection, the UE must consider that no sidelink DRX is to be applied for the specific sidelink unicast communication in question.