Find the area of $\Delta ABC$ where AC is focal chord of the parabola $y^2=4ax$ & B is the vertex of parabola $y^2=4ax$?

Question

$\begin{array}{1 1}(a)\;a^2|t_1t_2(t_1-t_2)|\\(b)\;a|t_1t_2(t_1t_2)|\\(c)\;2a^2|t_1t_2(t_1t_2)|\\(d)\;a^2|t_1t_2(t_1+t_2)|\end{array}$