What is the equation of the circle shown below?

The equation of a standard circle with radius r and centred at (a,b) is
(x-a)^2+(y-b)^2=r^2

As shown in the figure, circle has centre at (a,b)=(3,0) and a radius of r=8-3=5.

=>
equation of given circle
(x-3)^2+(y-0)^2=5^2 =>
x^2-6x+9 + y^2 = 25 =>

x^2 -6x +y^2 -16 = 0

Note that this does not match any of the four answers, unless there is a fifth answer that is not shown in the figure.