Gravitation between two objects increases when the distance between them decreases.
When the mass of an object increases, its gravitational pull also increases.
It would be a line going straight through the graph under the middle.
The answer is D. Exosphere
Exosphere is the outermost Layer of the Atmosphere that goes out about 500 - 10,000 Km in altitude.
It's the place where satellites and the space shuttle orbit the earth. Because it's difficult to define the boundary between exosphere and the outer space, exosphere may be considered as a part of outer space