In honey, with a picture, and a cyro solution.
Hope this helps!
Mesosphere is the layer after stratosphere, which is after troposphere, as seen from Earth in the direction of Space.
It starts at 60 km and ends at 120 km, after which comes the termosphere.
So we're looking for a line that's closest to 100 km, and this is the shortest line, A.
Greenland is part of North America, but Greenland is politically associated with Denmark/Norway.
