The equation of the circle whose two diameters are the lines \( x+y=4 \) and \( x-y=2 \) and which passes through \( (4 , 6 ) \) is

A \( x^2+y^2-6x-2y-16=0 \)

B \( x^2+y^2-6x-2y=15 \)

C \( x^2+y^2=0 \)