Passage Summary: The author argues that because some valid art is meant to make people angry and take action, it's incorrect to say that all valid art must be about beauty.

Conclusion: Critics are wrong to claim that being concerned with beauty is a requirement for all legitimate art.

Reasoning: Some legitimate art aims to provoke anger, and any art with that goal intentionally seeks to cause real-world intervention.

Analysis: This Sufficient Assumption question contains a classic 'gap' between two concepts: 'calling for concrete intervention' and 'not being concerned with beauty.' The author establishes that some art is legitimate and calls for intervention, then concludes that not all art is concerned with beauty. To make this logic bulletproof, we need an assumption that bridges these terms. Look for an answer that guarantees that if an artwork calls for concrete intervention, it cannot be concerned with beauty. This would force the conclusion to be true by making the two categories mutually exclusive.