Ans: C
Note that the first term and the common ratio of the positive terms in the geometric sequence are $4$ and $\dfrac{1}{4}$ respectively. Hence, we have
Note that the first term and the common ratio of the positive terms in the geometric sequence are $4$ and $\dfrac{1}{4}$ respectively. Hence, we have
$\begin{array}{rcl}
S(\infty) & = & \dfrac{4}{1-(\frac{1}{4})} \\
& = & \dfrac{16}{3}
\end{array}$
