AMC 12A 2011 Problem 17

Circles with radii 1, 2, and 3 are mutually externally tangent. What is the area of the triangle determined by the points of tangency?

Answer Choices
A. \dfrac{3}{5}
B. \dfrac{4}{5}
C. 1
D. \dfrac{6}{5}
E. \dfrac{4}{3}