Which series is a test case for the comparison test using ∑1n\sum \frac{1}{n}∑n1?
∑n=1∞1n+1\sum_{n=1}^{\infty} \frac{1}{n+1}∑n=1∞n+11
∑n=1∞1n2\sum_{n=1}^{\infty} \frac{1}{n^2}∑n=1∞n21
∑n=1∞1n!\sum_{n=1}^{\infty} \frac{1}{n!}∑n=1∞n!1
∑n=1∞2n\sum_{n=1}^{\infty} 2^n∑n=1∞2n