When the graphs of the quadratic function $y = f ( x )$ and the linear function $y = g ( x )$ are as shown in the figure, the sum of all natural numbers $x$ satisfying the inequality
$$\left( \frac { 1 } { 2 } \right) ^ { f ( x ) g ( x ) } \geq \left( \frac { 1 } { 8 } \right) ^ { g ( x ) }$$
is? [4 points]\\
\includegraphics[max width=\textwidth, alt={}, center]{ce47b871-6f7b-4821-9280-2ee0676a822e-05_528_477_731_1260}\\
(1) 7\\
(2) 9\\
(3) 11\\
(4) 13\\
(5) 15