In the diagram, AC=CB=10\:m, where AC and CB are each the diameter of the small equal semi-circles. The diameter of the larger semi-circle is AB. In travelling from A to B, it is possible to take one of two paths. One path goes along the semi-circular arc from A to B. A second path goes along the semi-circular arcs from A to C and then along the semi-circular arc from C to B. The differenc in the lengths of these two paths is
Answer Choices
A. 12\pi
B. 6\pi
C. 3\pi
D. 2\pi
E. 0