$P$ and $Q$ are two distinct points on the parabola, $y2=4x,$ with parameters $t$ and $t_1$ respectively. If the normal at $P$ passes through $Q$, then the minimum value of $t_1^2$ is :

Question

$\begin{array}{1 1}(1)\; 2\\ (2) \;4\\ (3)\; 6\\ (4)\; 8\end{array}$