If the circle x2+y2+2gx+2fy+c=0x^2 + y^2 + 2gx + 2fy + c = 0x2+y2+2gx+2fy+c=0 is tangent to both axes, which of the following is true?
g2=f2=cg^2 = f^2 = cg2=f2=c
g2+f2=cg^2 + f^2 = cg2+f2=c
g=f=cg = f = cg=f=c
g2=f2=−cg^2 = f^2 = -cg2=f2=−c