Which of the following is not a necessary condition for Cauchy's Mean Value Theorem?

Which of the following is not a necessary condition for Cauchy's Mean Value Theorem?

Explanation
Cauchy's Mean Value Theorem states that if two functions f(x) and g(x) are continuous on the closed interval [a, b] and differentiable on the open interval (a, b), and g'(x) ≠ 0 for any x in (a, b), then there exists a point c in (a, b) such that:
(f'(c) / g'(c)) = (f(b) - f(a)) / (g(b) - g(a))
The necessary conditions for Cauchy's Mean Value Theorem are:
  • 1. The functions f(x) and g(x) are continuous on [a, b].
  • 2. The functions f(x) and g(x) are differentiable on (a, b).
  • 3. g'(x) ≠ 0 for any x in (a, b).