well, a reflective essay would mean that you are writing about something from the past. so the first one would not be reflecting because time travel is something that has not happened yet, the second one is a topic not so much something you would reflect on, the last one is also a topic that you would not reflect on, so that leaves us with the third one even though you could have met your childhood hero yesterday you are still reflecting on your childhood and reflecting on when you met them. so I could go with "C". hope this helps :)
