The Graph of F Is Shown Below $f ^ {tt} ( x ) \text { zero? }$

Multiple Choice

The graph of f is shown below. For which value of x is $f ^ {tt} ( x ) \text { zero? }$

A) $x = 2$
B) $x = 0$
C) $x = - 2$
D) $x = 6$
E) $x = 4$