The equation of the circle passing through (2,1) and touching the co-ordinate axes, is :

Question

$(a)\;x^2+y^2-2x-2y+1=0$

$(b)\;x^2+y^2+2x+2y+1=0$

$(c)\;x^2+y^2-2x-2y-1=0$

$(d)\;x^2+y^2+2x-2y-1=0$