Directions: Choose the word that best substitutes the given phrase.
A form of government in which supreme authority is vested in a small, privileged elite.

The correct answer is Aristocracy.

Step-by-Step Breakdown:

1. Analyzing the Given Phrase:
The phrase describes a system of governance where power and supreme authority belong to a small, privileged upper class or elite group (historically associated with nobility, status, or inherited titles).

2. Etymology and Definition:
• Aristocracy: Derived from the Greek root words aristos (meaning "best") and kratos (meaning "rule" or "power"). Literally translating to "rule by the best," it refers to a form of government in which governance is vested in a privileged aristocracy or elite nobility.

3. Evaluating the Other Options:
• Oligarchy: A general system where power rests with a small group of people, but not necessarily defined by nobility or a traditionally privileged elite class (it could be based on wealth, military force, or political influence).
• Technocracy: A system of governance where technical experts, scientists, and engineers hold political authority based on their specialized knowledge.
• Autocracy: A government system in which supreme power is held by a single individual (such as a dictator or absolute monarch).

Hence, Aristocracy is the exact term that substitutes the given phrase.