A function g satisfies limx→3−x−3g(x)−g(3)=4 and limx→3+x−3g(x)−g(3)=−1. Which statement about g at x=3 is true?
a) g is differentiable at x=3 with g′(3)=23.
b) g is not differentiable at x=3 because the one-sided limits are unequal.
c) g is differentiable at x=3 with g′(3)=−1.
d) g is not continuous at x=3 because the one-sided limits are unequal.