By definition, a point is a local minimum if it has the smallest <em>y</em> coordinate in that interval and the graph goes from decreasing to increasing.
Based on this information, you can graph the points given in the problem above, as you can see in the figure attached. Then, you can notice that the ordered pair that is closest to a local minimum of the function is the last option shown in the problem.
$7 is the correct answer for *per hour*, as 9-2=7. Notice how it says how much did you earn last year, implying total earned. How many hours did you work last year?