# Suppose {$a_n$} be a sequence of posetive real numbers such that $a_n\ge a_{n+1}$ for all $n\ge1$ and $\sum_{n=1}^{\infty}a_n <\infty$

Suppose {$a_n$} be a sequence of posetive real numbers such that $a_n\ge a_{n+1}$ for all $n\ge1$ and $\sum_{n=1}^{\infty}a_n <\infty$ then which of the following(s) is true:

A. $\lim_{n\to \infty}a_n=0$

B.$\lim_{n\to \infty}na_n=0$

C.$\lim_{n\to \infty}n^2a_n=0$