Note: There may be some spanning tree topology that can never be generated by (STP) spanning tree protocol. I! you think a specific topolosy cannot be generated by STP protocol then you may want to mark it as not POSSIBLE. IT its turn out to be true, 1 mark will be awarded, If its turn out to be false, 1 mark will be deducted, if you leave ROO unanswered, then no mark will be awarded or deducted. In case of dispute, you strongly believe the topology