Question: Under what circumstances can the Drift RNS (DRNS) initiate the Radio Link Pre-emption procedure in a UTRAN Iur interface context?
Option 1: Only during initial setup of a new Radio Link for a UE.
Option 2: Exclusively when the UE Context is being modified.
Option 3: After a predetermined timer expires following Radio Link establishment.
Option 4: At any time after establishing a Radio Link, specifically when resources need to be freed.
Explanation: This answer is correct because, according to the specified procedure, the DRNS initiates the Radio Link Pre-emption when resources need to be freed, and this can occur at any point following the establishment of a Radio Link. This highlights the dynamic management of radio resources in UTRAN networks, allowing for efficient allocation and reallocation based on demand.