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Which of the following series converge?

I. $\sum_{n=1}^{\infty }\cfrac{5}{n^{1/4}} $II. $\sum_{n=1}^{\infty }\cfrac{2}{n^{4}}$III. $\sum_{n=1}^{\infty }\cfrac{3^{n}}{n^{3}}$

I only.

II only.

III only.

II and III.