Answer
Your feet should face either east or west.
Work Step by Step
As seen in Figure 33.31, scattered skylight is polarized in a north-south direction. Sunglasses have a vertical transmission axis. If your feet face west/east, the transmission axis of your sunglasses will also be along the east-west line.
The incoming light will have a polarization axis at right angles to that of your sunglasses, minimizing the transmission of the scattered skylight to your eyes.
