Answer:
A. -400
Explanation:
Slope of a line is defined as the change in the component of the y- axis to its x axis as shown;
slope = Δy/Δx =

From the graph, y2 = 0, y1 = 4000, x2 = 10, x1 = 0
slope =


The slope of the line is a negative slope and it is -400