Answer
choice $(A)$
Work Step by Step
Equation form:
$\displaystyle \quad f(x)=\frac{N}{1+Ab^{-x}}$,
where $N$ = limiting value,
Reading the graph, we see that:
$N=8,$ choice ($C$) is eliminated.
Initial value is $1$, so:
$f(0)=1\Rightarrow\left\{\begin{array}{ll}
1 & =\dfrac{8}{1+Ab^{0}}\\
1+A & =8\\
A & =8-1=7
\end{array}\right.\qquad\Rightarrow\qquad $choice $(A)$
