The distance between the chords of contact of tangents to the circle `x^2+y^2+2gx +2fy+c=0` from the origin & the point (g,f) is
A. `g^(2)+f^(2)`
B. `(1)/(2)(g^(2)+f^(2)+c)`
C. `(g^(2)+f^(2)+c)/(2sqrt(g^(2)+f^(2)))`
D. `(g^(2)+f^(2)-c)/(2sqrt(g^(2)+f^(2)))`
