Question: In a Background Data Transfer (BDT) configuration, what optional information can be included in BDT Policy requests to the 3GPP network, alongside an expected time window and UE set?
Option 1: Expected data volume per UE
Option 2: Guaranteed QoS parameters for each UE
Option 3: Specific network slice allocation for BDT
Option 4: Detailed user subscription information
Explanation: The correct answer is Option 1 because, according to the specifications, BDT Policy requests can include additional optional information such as "expected data volume per UE" beyond the mandatory expected time window and UE set. This detail is crucial for network resource planning and optimization during background data transfers. Options 2, 3, and 4 are not mentioned in the context as optional information for BDT Policy requests, making them incorrect choices.