$($a$)$ Tag the sentences below using the Penn Treebank part$-$of$-$speech tags $($Jurafsky and Martin, Figure $1$: $5\mathrm{.}6$ below$).$

i$.$ The leaders of tomorrow are speaking up today on the climate crisis.

ii$.$ Education also enables us to better discern fact from fiction. $($b$)$ Describe some of the challenges of automatic part$-$of$-$speech tagging.Penn Treebank part$-$of$-$speech tags $($including punctuation$).$