In a Graph with "Crop Yield" on the Vertical Axis

In a graph with "crop yield" on the vertical axis and "rainfall" on the horizontal axis, the vertical intercept refers to the

A) steepness or flatness of the graph.
B) amount of rainfall when "crop yield" is zero.
C) amount of crop yield when "rainfall" is zero.
D) total crop yield during a given period of time.