Answer
$a$ is the graph of $\int_{0}^{x}f(t)~dt$
$c$ is the graph of $f$
$b$ is the graph of $f'$
Work Step by Step
By comparing the graphs, we can see where each graph has a slope of 0 and where each graph crosses the x-axis. We can also determine where each graph has a positive or negative slope, and where each graph has positive or negative values. Thus, we can determine the following:
$c = a'$
$b = c'$
Therefore:
$a$ is the graph of $\int_{0}^{x}f(t)~dt$
$c$ is the graph of $f$
$b$ is the graph of $f'$