Answer: C) Stretched vertically by a factor of 4
This is another way of saying "the graph of g(x) is 4 times taller compared to f(x)".
Recall that anything of the form g(x) = k*f(x) will basically stretch f(x) vertically by a factor of k, where k is any real number. This is because y = f(x) and k*f(x) will move the y coordinate k times further away. For 4*f(x), the y coordinate is moved 4 times further away. Do this for every point, and you'll have the vertical stretch mentioned earlier.