Webwork A2 Question 10

I gave this question a try but it's not making any more sense:

The graph of the function $f(x)=-4^{x}$ can be obtained from the graph of $g(x)=4^{x}$ by one of the following actions:

I don't know how the changes are reflected on the graph...I'd say the function has shifted vertically. What would the range for this be? I am lost...a hint please, someone? Thanks kindly.

-- Arabella.