1. The sentence relies on a Direct Contrast signaled by the word "conversely."

- The Comparison: Fort Ancient vs. Mississippian groups.
- The Known Quantity: Fort Ancient is "profoundly egalitarian" (promoting equality and avoiding hierarchy).
- The Requirement: Since they "diverged sharply," the Mississippian power structure must be the opposite of egalitarian. We are looking for two words that describe top-down, domineering, or authoritative power.


2. Evaluating the Choices (Grammar & Logic Audit):
- A. capricious: (Logic Trap) Means unpredictable or whimsical. While a leader might be capricious, it isn't the direct logical antonym of "egalitarian."
- B. imperious: (Correct) Refers to assuming power or authority without justification; being arrogant and domineering. This is a perfect contrast to a society where everyone is equal.
- C. dubious: (Neutral Trap) Means hesitating or doubting; not to be relied upon. This doesn't fit the context of how power is exercised, only how it is perceived.
- D. peremptory: (Correct) Means insisting on immediate attention or obedience, especially in a brusque or imperious way. In a GRE context, imperious and peremptory are a frequent synonym pair used to describe autocratic behavior.
- E. utilitarian: (Thematic Trap) Designed to be useful or practical rather than attractive. This is a common "distractor" word in anthropology-themed questions but lacks the "dominance" required here.
- F. vacillating: (Opposite Trap) Means wavering between different opinions or actions; indecisive. An egalitarian society might actually be more prone to vacillation (due to consensus-building) than a top-down one.