Enter left, right, upward, downward, stretching or shrinking.
(a) The graph of $f(x)=(x+12)^2$ can be obtained from shifting the graph of $f(x)=x^2$ to the 12 units.
(b) The graph of $f(x)=x^2+12$ can be obtained from shifting the graph of $f(x)=x^2$ 12 units.
(c) The graph of $f(x)=12\sqrt{x}$ can be obtained by the graph of $f(x)=\sqrt{x}$ vertically by a factor 12.
(d) The graph of $f(x)=\sqrt{12 x}$ can be obtained by the graph of $f(x)=\sqrt{x}$ horizontally by a factor $\frac{1}{12}$.