Passage Summary: To keep a democracy stable and prevent people from fighting over wealth, we need a growing economy so everyone has a chance to move up the social ladder.

Conclusion: Democratic societies ought to implement policies that guarantee continuous economic growth.

Reasoning: Class divisions and low social mobility threaten democracy by creating divisive political factions, and economic expansion provides the necessary opportunities for people to improve their status.

Analysis: The author assumes that economic expansion is the primary or most effective way to ensure the social mobility required for a healthy democracy. It’s a bit like saying the only way to keep a dinner party peaceful is to keep bringing out more food so no one fights over the last appetizer. To strengthen this, we need to bridge the gap between 'expansion' and 'reduced class division.' Look for an answer that confirms economic growth actually leads to mobility or suggests that without growth, these dangerous class divisions are much harder to bridge.