Answer
$(A)$
Work Step by Step
Goal: $\displaystyle \quad f(x)=\frac{N}{1+Ab^{-x}}$,
where $N$ = limiting value = 15 (B and C are eliminated.)
Cases A and D both have A=8.6, so we don't observe $f(0)$.
The graph is rising, so $b\gt 1, $ eliminating D.
