The radius of a circle is $$\frac{1}{3}$$~the length of the side of the square. How many times the perimeter of a square is the diameter of a circle? 
选项为:A:$$\frac{1}{3}$$  B:$$\frac{1}{6}$$  C:$$1$$  D:$$2$$  E:$$4$$  请回答其中一个选项.