Suppose f(x) = x^2 and g(x) = (1/3x)^2. Which statement best compares the graph of g(x) with the graph of f(x)?
A. The graph of g(x) is shifted 3 units to the right.
B. The graph of g(x) is horizontally stretched by a factor of 3.
C. The graph of g(x) is horizontally compressed by a factor of 3.
D. The graph of g(x) is vertically compressed by a factor of 3.