(a,0) and (b, 0) are centres of two circles belonging to a co-axial system of which y-axis is the radical axis. If radius of one of the circles 'r', then the radius of the other circle is

Options

A. `(r^(2) + b^(2) + a^(2) )^(1//2)`
B. `(r^(2) + b^(2) - a^(2))^(1//2)`
C. `(r^(2) + b^(2) - a^(2))^(1//3)`
D. `(r^(2) + b^(2) + a^(2))^(1//3)`

Answer

B