Mount St. Helens, a volcano, was known as the Mount Fuji of the West. Before it blew its top in the 1980s, the pyramid shape of Mount St. Helens, in the Cascade Range of Washington State, did indeed look like the Japanese mountain. We used to call it "the mountain you could climb in tennis shoes" because it wasn't very steep or high. Though it took hours to drive from our home, our family trekked there every September for one great reason—blueberries. The wild blueberries on the lower slopes were easily accessible, just below the parking lot. Our family would spread out among the bushes, which were fairly far apart near the timberline. There were no tall trees, either. This meant my parents could easily keep an eye on my brothers and me. Mostly, I remember the quiet in the mountains. With no sound around us except the squawk of blue jays and the whistle of a mountain breeze, we filled coffee cans to the brim with blueberries, eating a good handful as we went. Each year, we picked enough to fill our freezer, plenty for pancakes and pies for months to come. The mountain holds other memories for me, too. My favorite is the sudden snowstorm we encountered one year, catching us by surprise and turning the blueberry bushes a sparkly white. Even the parking lot holds a piece of my past. My father taught me to drive there. He gave me gentle direction as I maneuvered the car around the lampposts. Mount St. Helen erupted in 1980, forever flattening its pointed top. Though it stands now as a shadow of its former beauty, some days I can still see the pyramid it once was, perfect in my memory. Why does the author use the word shadow in the fourth paragraph?
A. to explain why one side of the mountain appears darker than the other
B. to suggest that the mountain has many undiscovered regions
C. to show that the mountain is less impressive than before its eruption
D. to demonstrate how the mountain darkens the areas around it