A figure is constructed using fourteen 1 \times 1 \times 1 cubes. Nine of the 1 \times 1 \times 1 cubes are used to make the bottom layer and five additional 1 \times 1 \times 1 cubes are positioned on top of the bottom layer. The figure is shown from two different perspectives.
An ant begins at P and walks a distance d on the surface of the figure to arrive at Q. The smallest possible value of d is closest to
Answer Choices
A. 6.43
B. 6.40
C. 6.71
D. 6.66
E. 6.48