Answer:
around 30 km
Step-by-step explanation:
Earth's atmosphere is about 300 miles (480 kilometers) thick, but most of it is within 10 miles (16 km) the surface.
What i got is not any of your selection but:
- 1 million meters are the same as 1000 km and the atmosphere of the earth is not that thick
- 500m is absolutely wrong cus even normal plane flight at 10 000m
So the only option is 30 km
Hope this helped :3