The domain of the function $h$ graphed below is all real numbers, and all of its extreme values occur when $-3<x<3$. Use the graph to answer the following questions.

Identify all of the values of $c$ for which $h'(c)=0$. If there is more than one value, enter the values as a comma-separated list. If there are none, enter DNE.
values:

Identify all of the values of $c$ for which $h'(c)$ does not exist. If there is more than one value, enter the values as a comma-separated list. If there are none, enter DNE.
values: