door bell rang at 5:30 am

I woke up around 5:30 am, trying to get back to sleep. Then out of no where, I heard my door bell ring. All of a sudden I felt freaky. Of course I did not jump out of bed to answer the door. But could not stop playing all possibly scenario in my mind...

1. Some kid was playing a prank (he/she was surely an early bird)
2. some other wireless device triggered my wireless bell remotely (what a coincidence ??)
3. my kitty jumped out high and accidentally pressed the button (pretty hard to picture that)
4. some small stone hit the button (did not hear strong wind outside)
5. solicitor --- must be out of their mind to think people would say 'yes' at 5:30 am
6. my front yard sprinkler went out of order and water shoot out sky high, someone walked by and tried to tell me about it (timer has been reset to 7 am already if I recall correctly)
7. my kitty got trapped again in back door neighbor's house, and they stopped by to tell me (5:30 am? last time they posted a note on my door)
8. danger happened, someone was trying to alert me to leave the house (should I really jump out?)
9. ghost?

... I decided if there to be real danger, the door bell would probably ring again... I felt into asleep...