Three unit squares and two line segments connecting two pairs of vertices are shown. What is the area of $\triangle ABC$?
$\textbf{(A)}\ \frac16 \qquad$ $\textbf{(B)}\ \frac15 \qquad$ $\textbf{(C)}\ \frac29 \qquad$ $\textbf{(D)}\ \frac13 \qquad$ $\textbf{(E)}\ \frac{\sqrt{2}}{4}$