The graph of [math] (not [math]) is given below.

graph of function
(Note that this is a graph of [math], not a graph of [math].)

At which of the marked values of [math] is
A. [math] greatest? [math]
B. [math] least? [math]
C. [math] greatest? [math]
D. [math] least? [math]
E. [math] greatest? [math]
F. [math] least? [math]