Find the equation of tangent to the parabola $(y-6)^2=4a(x-p)$ at $(at^2,2at)$?

Question

$\begin{array}{1 1}(a)\;t(y+b)=x-p+at^2\\(b)\;t(y-b)=x-p+at^2\\(c)\;t(y+b)=x+p+at^2\\(d)\;t(y+b)=x+p-at^2\end{array}$