A. a√2

B. a√3

C. 2a

D. none

The length of the intercept made by the circle x^{2}+y^{2}-12x+14y+11=0 on x-axis is

I: The equation of the circle concentric with x^{2}+y^{2}-2x+8y-23=0 and passing through (2, 3) is x^{2}+y^{2}-2x+8y-33=0

II: : The equation of the circle passing through the points (1, 1), (2, -1), (3, 2) is x^{2}+y^{2}-5x-y+4=0

If a circle passes through the point (a, b) and cuts the circle x^{2}+y^{2}=4 orthogonally, then the locus of its centre is

The line 4x+4y-11=0 intersects the circle x^{2}+y^{2}-6x-4y+4=0 at A and B. The point of intersection of the tangents A, B is

If 4l^{2}-5m^{2}+6l+1=0, then the line lx+my+1=0 touches the circle