Use the appropriate test to decide whether the following series converge or not:

a) $\displaystyle \sum \limit_{n=1} ^{\infty} \frac{3n^2 - 2n + 1}{2n^2 + 5}$

b) $\displaystyle \sum \limit_{n=1} ^{\infty} \frac{3n^2 - 2n + 1}{2n^4 + 5}$

c) $\displaystyle \sum \limit_{n=1} ^{\infty} \frac{n^3 4^n}{3(n!)}$

d) $\displaystyle \sum \limit_{n=1} ^{\infty} \frac{2 + 3 sin~n}{5n^2 + 2}$

Could someone please help :-). Thank you