The equation of the circle having its centre on the line `x+2y-3=0` and passing through the points of intersection of the circles `x^2+y^2-2x-4y+1=0a n dx^2+y^2-4x-2y+4=0` is `x^2+y^2-6x+7=0` `x^2+y^2-3y+4=0` c.`x^2+y^2-2x-2y+1=0` `x^2+y^2+2x-4y+4=0`