A. x2+y2-4x-6y+4=0

B. x2+y2+6x-8y+16=0

C. x2+y2-8x-6y+21=0

D. x2+y2-24x-10y+144=0

The centre of the circle (1+m^{2})(x^{2}+y^{2})-2cx-2cmy=0 is

The equation of the circle which cuts orthogonally the three circles x^{2}+y^{2}+4x+2y+1=0, 2x^{2}+2y^{2}+8x+6y-3=0 , x^{2}+y^{2}+6x-2y-3=0 is

If the lines 3x-4y-7 =0and 2x-3y-5=0 are two diameters of a circle of area 49π sq unit. Then the equation of this circle is

The number of common tangents to the circles x^{2}+y^{2}+2x+8y-23=0, x^{2}+y^{2}-4x-10y+19=0 is

If the lines 2x-3y=5 and 3x-4y=7 are two diameters of a circle of radius 7, then the equation of the circle is