Answer: A, because the equation of a circle is [tex](x-h)^2+(y-k)^2=r^2[/tex]. So, if the point of the center is [tex](5,7)[/tex] and the radius [tex]2[/tex] , then on the equation should be changed as negative and the radius should be multiplied as [tex]4[/tex], which is [tex](x-5)^2+(y-7)^2=4[/tex]
