18. Figure 3 shows the graph of the derivative of a function f. Use the graph to answer the following questions about the original function f. Figure 3 (a) State the interval(s) upon which f is increasing. (b) State the interval(s) upon which f is decreasing. (c) State the interval(s) upon which f is concave up. (d) State the interval(s) upon which f is concave down. (e) State the number(s) where f has a local maximum. (f) State the number(s) where f has a local minimum