Which series diverges by the Test for Divergence?
∑1n2\sum \frac{1}{n^2}∑n21
∑nn+1\sum \frac{n}{n+1}∑n+1n
∑12n\sum \frac{1}{2^n}∑2n1
∑(−1)nn\sum \frac{(-1)^n}{n}∑n(−1)n