Final answer:
The riotous capital of Hell in Milton's 'Paradise Lost' is Pandemonium, where the fallen angels deliberate their future.
Step-by-step explanation:
The riotous capital of Hell in John Milton's epic poem "Paradise Lost" is a) Pandemonium. The term 'Pandemonium' originates from Milton's masterpiece and literally means 'all demons' or 'a place of all demons.' In the poem, Pandemonium is the capital where the fallen angels gather to deliberate their future after being expelled from Heaven. It is depicted as a grand palace, which, despite its chaotic connotations, is Milton’s imaginative center of infernal governance and the meeting place of the demonic council, demonstrating the poet's creative blending of classical and biblical mythology.