The correct options are
A C1 passes through the centre of C2
C C2 passes through the centre of C1
D sum of the radii of C1 and C2 is twice the radius of C3.
Centers of C1, C2 and C3 are (−1,0), (1,0) and (0,1) respectively.
Since, (1,0) satisfies C1
Therefore, C1 passes through the centre of C2
and (−1,0) satisfies C2
Therefore, C2 passes through the centre of C1
now, r1=√1+3=2
Similarly, r2=r3=2
Therefore, r1+r2=2r3