The value of$'c'$ of Lagranges Mean Value Theorem for $f(x)=\sqrt{x}$ when $a=1$ and $b=4$ is

Question

$$\begin{array} (1)\frac{9}{4}&(2)\frac{3}{2}\\(3)\frac{1}{2}&(4)\frac{1}{4} \end{array}$$