An equilateral triangle SAB is inscribed in the parabola y2 = 4ax having it’s focus at ‘S’. If chord AB lies towards the left of S, then side length of this triangle is
(a) 3a(2 – √3 )
(b) 4a(2 – √3 )
(c) 2(2 – √3 )
(d) 8a(2 – √3)