The Graph Shows the Total Sales in Thousand of Dollars $\frac{3}{2}$

Multiple Choice

The graph shows the total sales in thousand of dollars from the distribution of x thousand catalogs. Find the average rate of change of sales with respect to the number of catalogs distributed for the change in x.

-20 to 50

A) $\frac{3}{2}$
B) $\frac{2}{5}$
C) $\frac{2}{3}$
D) $\frac{5}{2}$