Final answer:
Shelley's 'Ozymandias' explores the impermanence of power and the eventual downfall of tyrants, symbolized by a ruined statue, signifying the faded legacy of an ancient ruler.
Step-by-step explanation:
The main theme of Shelley's poem 'Ozymandias' is the transient nature of power and the inevitable decline of rulers and empires over time, which aligns with option 1) The mockery of tyranny and the inevitable downfall of powerful rulers. In the poem, the once-great king Ozymandias is symbolized by a dilapidated statue in a vast desert, showing how his legacy and empire have crumbled. This theme reflects Shelley's own political views and criticism of the establishment, particularly in the context of the Industrial Revolution and the growing disparities of the working class he explored in his other works such as 'England in 1819' and 'Song to the Men of England.