[" The differential equation of the family of circles with fixed radius "5" units and centre on the line "y=2" is: "],[[" (1) "quad (x-2)y^(prime2)=25-(y-2)^(2)," (2) "quad (y-2)y^(prime2)=25-(y-2)^(2)],[" (3) "quad (y-2)^(2)y^(prime2),=25-(y-2)^(2)," (4) "quad (x-2)^(2)y^(prime2)=25-(y-2)^(2)]]