we know that
An exponential function is a function where the input, x, appears in the exponent.
the equation of an exponential function usually looks like:
\(y=ab^{x}\)
where
a is a number called the initial value
b is a number called the growth factor
In this problem
we have
\(f(x) =\frac{1}{5}(15^{x})\)
where
\(\frac{1}{5}\) -------> is the initial value
\(15\) ------> is the growth factor
therefore
the answer is the option
\(D. 15\)
