A dance programme is scheduled for $10.00$ a.m. Some students are participating in the programme and they need to come an hour earlier than the start of the event. These students should be accompanied by a parent. Other students and parents should come in time for the programme. The instruction you think that is appropriate for this is
- Students should come at $9.00$ a.m. and parents should come at $10.00$ a.m.
- Participating students should come at $9.00$ a.m. accompanied by a parent, and other parents and students should come by $10.00$ a.m.
- Students who are not participating should come by $10.00$ a.m. and they should not bring their parents. Participating students should come at $9.00$ a.m.
- Participating students should come before $9.00$ a.m. Parents who accompany them should come at $9.00$ a.m. All others should come at $10.00$ a.m.