At a point P on the parabola y²=4ax, tangent and normal are drawn. Tangent intersects the x-axis at Q and normal intersects the curve at R such that chord PQ subtends an angle of 90∘ at its vertex. Then
A PQ=2a√6
B PR=6a√3
C area of ΔPQR=18√2a2
D PQ=3a√2