If all you want is a horizontal shrink then the answer you choose should not be in brackets. The brackets will alter the way the graph looks.
That means that A and B are not correct.
If you have a graph where a>1 the graph will expand.
If you have a graph where a<1 but greater than 0 the graph will shrink.
y = 1/2 x^3 + 4 is the answer you want.
Just to show you the graphs, I have enclosed a graph of the three choices.
y = x^3 + 4 is red
y = 2x^3 + 4 is blue
y = (1/2) x^3 + 4 is green. The green one is the one you want.
