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

• A. The functions, f(x) and g(x) be continuous in [a, b]
• B. The derivation of g'(x) be equal to 0
• C. The functions f(x) and g(x) be derivable in (a, b)
• D. There exists a value c (a, b) such that, ( frac{f(b)-f(a)}{g(b)-g(a)} = frac{f'(c)}{g'(c)} )