Final answer:
The best description of irony in 'A Man Said to the Universe' is that the universe's response to the man, albeit dismissive, ironically acknowledges his existence.
Step-by-step explanation:
The irony in the poem A Man Said to the Universe is best described by Option 2: The universe acknowledges the man’s existence simply by responding to him. This presents an ironic situation because the man is seeking recognition from the vast universe, which is indifferent and unconcerned with human affairs. Yet, in the act of responding, even if only to deny the man's importance, the universe inadvertently gives him a form of the very recognition he seeks. The poem plays on the tension between human self-importance and the vast, impersonal cosmos.