Which of the following is/are true for a series of real numbers $\sum a_{n}$?\\
(A) If $\sum a_{n}$ converges then $\sum a_{n}^{2}$ converges;\\
(B) If $\sum a_{n}^{2}$ converges then $\sum a_{n}$ converges;\\
(C) if $\sum a_{n}^{2}$ converges then $\sum \frac{1}{n} a_{n}$ converges;\\
(D) If $\sum |a_{n}|$ converges then $\sum \frac{1}{n} a_{n}$ converges;