The function g is continuous on the closed interval [−4,6] and has critical points at x=−1 and x=3. Which of the following lists includes every x-value that must be examined to determine the absolute extrema of g on [−4,6]?
a) x=−1,3 only
b) x=−4,6 only
c) x=−4,−1,3,6
d) x=−4,−1,0,3,6