Geologists study sedimentation by drilling tubular core samples. Studies show that the mean sedimentation rate at the bottom of Devil's Lake, North Dakota, is about 0.24 cm per year. In 1980, the total thickness of the sedimentary layers at a certain location was 20 cm. What is the slope of the graph?
a) 0.012
b) 1.2
c) 8.3
d) 83
