The Graph of an Exponential Function Is Given $f ( x ) = 2 ^ { - x }$

Multiple Choice

The graph of an exponential function is given. Match the graph to one of the following functions.
- A) $f ( x ) = 2 ^ { - x }$
B) $f ( x ) = - 2 ^ { - x }$
C) $f ( x ) = 2 ^ { x }$
D) $f ( x ) = - 2 ^ { x }$