Question: What triggers the establishment of a new PDU session in a network slice towards a data network (DN) by the UE?
Option 1: When the UE receives a request from the DN to establish a new PDU session.
Option 2: When there is no established PDU session adequate for the PDU transmission and the UE needs to enable PDU transmission in a network slice.
Option 3: When the S-NSSAI included in the allowed NSSAI of the serving PLMN or SNPN changes.
Option 4: When the UE's local configuration is updated.
Explanation: The correct answer is Option 2 because, according to the text, the UE requests establishment of a new PDU session when there is no established PDU session adequate for the PDU transmission and it needs to enable PDU transmission in a network slice. This is based on the URSP rules or UE local configuration.