The radius of a circle is $$\frac{1}{2}$$~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:$$\frac{1}{4}$$  B:$$\frac{1}{2}$$  C:$$2$$  D:$$4$$  E:$$8$$  请回答其中一个选项.