Question: When setting the contents of the MBS Interest Indication, under what condition(s) does the UE include `mbs-Priority` in the indication?
Option 1: If the UE has a valid version of SIB21 for the PCell and the set of MBS frequencies of interest is not empty.
Option 2: If the UE prioritises reception of all indicated MBS frequencies above reception of any unicast bearers and multicast MRBs.
Option 3: If SIB20 is provided for the PCell or for the SCell, indicating available MBS services.
Option 4: If nonServingCellMII is included in SIB1 for the PCell, enabling MBS on non-serving cells.
Explanation: The correct answer directly aligns with the specification that `mbs-Priority` is included if the UE prioritises MBS broadcast reception over unicast bearers and multicast MRBs, highlighting a crucial aspect of managing resource allocation between broadcast and unicast/multicast services in NR networks.