While on a trip, you notice that the video screen on the airplane, in addition to showing movies and news, records your altitude (in kilometers) above the ground.

As the plane starts its descent
(at time x = 0), you record the following data: Time, x (min.) Altitude, y (km)
12 0 10 8 16 16 18 4 110 12

If you were to graph these points on a graph, you would notice that the line that forms represents a linear function. What is the practical meaning of slope in this situation?

a. For every minute that passes, the airplane descends 1 kilometer.
b. For every minute that passes, the airplane ascends 1 kilometer.
c. For every 2 minutes that passes, the airplane descents 1 kilometer.
d. For every minute that passes, the airplane ascends 2 kilometers. C. ​