The correct option is B (a,0)
Given parabola is y2=4ax
Let P(at21,2at1) and Q(at22,2at2) be two points on the parabola.
Slope of normal at P is m1=−t1
Slope of normal at Q is m2=−t2
∵ normals are perpendicular to each other,
∴m1m2=−1⇒t1t2=−1
which is the required condition for focal chord.
So, chord passes through the fixed point (a,0)