<h2>
Answer:</h2>
Option: A is the correct answer.
A. All positive real numbers.
<h2>
Step-by-step explanation:</h2>
<u>Domain of a function--</u>
It is the set of all the possible x values for which a function is defined.
<u>Range of a function--</u>
It is the set of all the values which is attained by the function in it's specified domain.
We are given a exponential function f(x) by:
We know that domain of such a function is all the real numbers.
But the function:
for all the x.
Hence, the range is all positive real numbers.
Also, by the graph of the function this may be observed( since, the graph lie above the x-axis )