Write the products of the reaction of furan with each of the following reagents:
(a) $\mathrm{Br}_{2}$, dioxane, $0^{c} \mathrm{C}$
(b) $\mathrm{HNO}_{2}$, acetic anhydride
(c) $\mathrm{CH}_{\mathrm{a}} \mathrm{COCl}, \mathrm{SnCl}_{4}$
(d) $\mathrm{H}_{2} / \mathrm{Pd}$
(e) $\mathrm{SO}_{3}$, pyridine