Ans: D
Note that $g(x) = f\left(\dfrac{x}{2}\right)$ means $f(x)$ is enlarged to $2$ times of its original along the $x$-axis.
Note that $g(x) = f\left(\dfrac{x}{2}\right)$ means $f(x)$ is enlarged to $2$ times of its original along the $x$-axis.
If the graph is enlarged to $2$ times of original along the $x$-axis, the $y$-intercept of the graph will remain unchanged and the $x$-intercepts of the graph will be multiplied by $2$.
Hence, the answer is D.
