Four cubes with edge lengths 1,2,3, and 4 are stacked as shown. What is the length of the portion of \overline{X Y} contained in the cube with edge length 3 ?
Answer Choices
A. \dfrac{3 \sqrt{33}}{5}
B. 2 \sqrt{3}
C. \dfrac{2 \sqrt{33}}{3}
D. 4
E. 3 \sqrt{2}