Answer: The correct answer is Option C.
Step-by-step explanation:
We are given:
Variable on X-axis = Volume
Variable on Y-axis = Mass
Slope is defined as the ratio of change in Y-axis to the change in X-axis. The representation for slope is:

Density of a substance is defined as the ratio of object's mass and volume.
So, the slope of the given graph represents density.
Hence, the correct answer is Option C.