A triangle is formed by the lines whose combined equation is given by (x+y−4)(xy−2x−y+2)=0. The equation of its circumcircle is
a. x² + y² – 5x – 3y + 8 = 0
b. x² + y² – 3x – 5y + 8 = 0
c. x² + y² – 5x -3y – 8 = 0
d. none of these