Mrs. Strunk's Earth Science class used an erosion model to investigate the relationship between the slope of a hill, or incline, and the amount of soil that washes off of the incline.

The class increased the slope of the incline from 1 to 5. Then, they poured 100 ml of water down the incline. Finally, they collected the soil from a tray at the bottom of the incline, dried the soil in an oven, and used a balance to find the mass of the soil. The data from their study is shown below.

Based on the graph, more soil is washed away when
A.
the soil is made mostly of sand.
B.
there are fewer rocks in the soil.
C.
the slope of the incline is less steep.
D.
the slope of the incline is steeper.