AMC 10B 2006 Problem 6

A region is bounded by semicircular arcs constructed on the side of a square whose sides measure 2 / \pi, as shown. What is the perimeter of this region?

Answer Choices
A. \dfrac{4}{\pi}
B. 2
C. \dfrac{8}{\pi}
D. 4
E. \dfrac{16}{\pi}