The correct options are
A (−2,0)
C (4,0)
Equation of the given circle can be written as
(x2+y2−2x−8)−2a(y)=0
which represents a family of circles passing through the intersection of the circle x2+y2−2x−8=0 and the line y=0.
The circle and the line intersect at the points P(−2,0) and Q(4,0).