Passage Summary: The author thinks that because every deal you make creates a duty, every duty you have must have come from a deal you made.

Conclusion: Legal obligations are essentially the same thing as requirements to fulfill an agreement.

Reasoning: Because making an agreement creates an obligation, the author assumes that having an obligation must mean an agreement was made.

Analysis: This argument commits a classic formal logic error known as a 'Mistaken Reversal.' The premise states that 'Agreement implies Obligation,' but the author concludes that 'Obligation implies Agreement.' In your search for the right answer, look for a description of this conditional error—specifically, that the author treats a condition that is sufficient for an obligation (making an agreement) as if it were a necessary requirement for an obligation. It ignores the possibility that you could have a legal obligation, like paying taxes or stopping at a red light, without ever having signed a specific agreement to do so.