The minimum distance of a point on the curve $y=x^2−4$ from the origin is :

Question

$\begin{array}{1 1} (1) \large\frac{\sqrt {19}}{2} \\ (2) \sqrt{\large\frac{15}{2}} \\ (3) \large\frac{\sqrt{15}}{2} \\ (4)\sqrt{ \large\frac{19}{2} } \end{array} $