Which of the following series converges absolutely?
∑n=1∞(−1)nn\sum_{n=1}^{\infty} \frac{(-1)^n}{n}∑n=1∞n(−1)n
∑n=1∞(−1)nn2\sum_{n=1}^{\infty} \frac{(-1)^n}{n^2}∑n=1∞n2(−1)n
∑n=1∞(−1)nn\sum_{n=1}^{\infty} \frac{(-1)^n}{\sqrt{n}}∑n=1∞n(−1)n
∑n=1∞(−1)nln(n)\sum_{n=1}^{\infty} (-1)^n \ln(n)∑n=1∞(−1)nln(n)