2. Do the following series converge or diverge? Write one sentence to explain your answer,and specify which test you used [3 marks each]. \text { (b) } \sum_{n=0}^{\infty} \frac{1}{n \sqrt{n}+3} \text { (c) } \sum_{n=1}^{\infty} \frac{1}{\sqrt{n}+n} \text { (d) } \sum_{n=3}^{\infty} \frac{(\ln n)^{3}}{n} \sum_{n=1}^{\infty} \frac{(-1)^{n}-1}{n}