Cho hàm \(f\left( x \right)\) liên tục trên khoảng là \(\left( {a;b} \right)\), \({x_0} \in \left( {a;b} \right)\).

A. \(\mathop {\lim }\limits_{x \to 0} \frac{{\Delta y}}{{\Delta x}}\). 

B. \(\mathop {\lim }\limits_{\Delta x \to 0} \frac{{\Delta y}}{{\Delta x}}\). 

C. \(\mathop {\lim }\limits_{\Delta x \to 0} \frac{{\Delta x}}{{\Delta y}}\). 

D. \(\mathop {\lim }\limits_{x \to 0} \frac{{\Delta y}}{x}\).