If f(x) = x^3, which of the following describes the graph of f(x − 3)?
the graph of f(x − 3) is a vertical shift of f(x) = x^3 three units up.
the graph of f(x − 3) is a vertical shift of f(x) = x^3 three units down.
the graph of f(x − 3) is a horizontal shift of f(x) = x^3 three units to the right.
the graph of f(x − 3) is a horizontal shift of f(x) = x^3 three units to the left.