The correct answer is: Only assumption I is implicit.
The statement “A Notice Board at a ticket window: ‘Please come in queue.'” implies that people need to be instructed to form a queue. This is because people may not naturally form a queue, or they may not form a queue in an orderly manner. The statement does not imply that people want to purchase tickets. It is possible that people are only forming a queue because they are required to do so.
Assumption I is implicit because the statement implies that people need to be instructed to form a queue. Assumption II is not implicit because the statement does not imply that people want to purchase tickets.