Answer:
The correct option is C.
Step-by-step explanation:
Range is the set of output or the values of the function.
The given function is

If a exponential function is defined as g(x)=a^x, where a>0, then the value of g(x) is always greater than 0, g(x)>0.
It means,

Multiply both sides by 9.



The value of the function f(x) is always greater than 0, therefore the range of the function is
Range = { y | y>0}
Hence the correct option is C.