If f is continuous for a ≤ x ≤ b and differentiable for a < x < b, which of the following could be false:
a) f'(c) = f(b) - f(a)/b-a for some c such that a < b < c.
b) f'(c) = 0 for some c such that a < c < b
c) f has a minimum value on a ≤ x ≤ b
d) f has a maximum value on a ≤ x ≤ b