The graph of f(x) = x2 was transformed to create a graph g(x) =f(x)−6. Which statement about the graphs is true?

A) The vertex of the graph of g is 6 units above the vertex of the graph of f.

B) The vertex of the graph of g is 6 units to the right of the vertex of the graph of f.

C) The vertex of the graph of g is 6 units to the left of the vertex of the graph of f.

D) The vertex of the graph of g is 6 units below the vertex of the graph of f.