In the diagram, \triangle{PQR} is equilateral and has side length 6\:cm. Each of the shaded triangles is equilateral and has side length 2\:cm. What fraction of the area of \triangle{PQR} is shaded?

**Answer Choices**

A. \frac37

B. \frac13

C. \frac12

D. \frac35

E. \frac23