Which of the following statement is correct ?

Options

A. The derivative of a function f(X) at a point will exist if t here is one tangent to the curve y= f(x) at that point and the tangent is parallel to y adis
B. The derivativbe of function (x) at a point will exist if there is one tangent to the curve y =f(x) at that point and the tangent must be parallel to x axis
C. The derivative of a function f(X) at point will exist if there is oe and only one tangent to the curve y = f(x) at the point and the tangent is not parallel to y axis
D. none of the abvoe

Answer

C

Explanation

It is obvious