4 Sequences \(\mathrm { A } , \mathrm { B }\) and C are shown below. They each continue in the pattern established by the given terms.
$$\begin{array} { l l l l l l l l l }
\text { A: } & 1 , & 2 , & 4 , & 16 , & 32 , & \ldots &
\text { B: } & 20 , & - 10 , & 5 , & - 2.5 , & 1.25 , & - 0.625 , & \ldots
\text { C: } & 20 , & 5 , & 1 , & 20 , & 5 , & 1 , & \ldots
\end{array}$$
- Which of these sequences is periodic?
- Which of these sequences is convergent?
- Find, in terms of \(n\), the \(n\)th term of sequence A .