The Graph Shows the Depth of Water W in a Reservoir

Multiple Choice

The graph shows the depth of water W in a reservoir over a one-year period as a function of the number of days x since the beginning of the year. Estimate the average rate of change of W between x = 0 and x= 100?

A) $- 2 \mathrm { ft } / \mathrm { day }$
B) $- 4 \mathrm { ft } / \mathrm { day }$
C) $4 \mathrm { ft } / \mathrm { day }$
D) $\frac { 1 } { 4 } \mathrm { f } / \mathrm { day }$
E) none of these