Which of the following explains how to obtain the graph of $y=-2^{-x}$ from the graph of $y=2^x$?

(a) Reflect the graph of $y=2^x$ about the $y$-axis and then reflect this result about the $x$-axis.
(b) Reflect the graph of $y=2^{-x}$ about the $y$-axis.
(c) None of the above.