AMC 10A 2012 Problem 15

Three unit squares and two line segments connecting two pairs of vertices are shown. What is the area of \triangle A B C ?

Answer Choices
A. \dfrac{1}{6}
B. \dfrac{1}{5}
C. \dfrac{2}{9}
D. \dfrac{1}{3}
E. \dfrac{\sqrt{2}}{4}