IS 0 IS COMPLEX NO OR NOT ???? IF SO WHAT WOULD BE THE CORRECT ANSWER OF UNDERMENTIONED QUESTION?

THE NUMBER OF COMPLEX NO Z SUCH THAT

|Z-1| = |Z + 1| = | Z - i | EQUAL

1) 1

2) 2

3) INFINITY

4) 0

 INFINITY

Its obvious that the circumcentre of the triangle formed by (-1,0), (1,0) and (0,1) will be the unique point that is equidistant from the three points (It lies on the perpendicular bisector of the lines joining any pair of the given points and we know that points on the perpendicular bisector are equidistant from the end-points of the line-segment)