The graph of $f'$ (not $f$) is given below.

(Note that this is a graph of $f'$, not a graph of $f$.)

At which of the marked values of $x$ is
A. $f(x)$ greatest? $x =$
B. $f(x)$ least? $x =$
C. $f'(x)$ greatest? $x =$
D. $f'(x)$ least? $x =$
E. $f''(x)$ greatest? $x =$
F. $f''(x)$ least? $x =$