For each given $p$ -series, identify $p$ and determine whether the series converges.
$$
\text { (a) } \sum_{k=1}^{\infty} k^{-4 / 3} \text { (b) } \sum_{k=1}^{\infty} \frac{1}{\sqrt[4]{k}} \quad \text { (c) } \sum_{k=1}^{\infty} \frac{1}{\sqrt[3]{k^{5}}} \quad \text { (d) } \sum_{k=1}^{\infty} \frac{1}{k^{\pi}}
$$