Defining Pareto Optimum

The statement "no one can be made better off without making someone worse off" is the definition of a Pareto Optimum. This concept describes a state of resource allocation where it's impossible to reallocate resources to make any one individual or group better off without making at least one other individual or group worse off.

Analyzing Economic Concepts

Let's examine why Pareto Optimum is the correct answer and differentiate it from the other options:

• Pareto Optimum: This is a state of economic efficiency. Once achieved, any further change to benefit one party necessitates harming another. It represents the point where maximizing overall welfare, given the constraints, is achieved without causing detriment to any single entity.
• Nash Equilibrium: Primarily used in game theory, a Nash Equilibrium occurs when no player can improve their outcome by unilaterally changing their strategy, assuming others' strategies remain fixed. It focuses on strategic stability, not necessarily overall economic efficiency or the specific trade-off described.
• Low-level Equilibrium Trap: This concept, often discussed in development economics, describes a situation where an economy is stuck at a subsistence level due to a lack of savings and investment, making it hard to grow. It doesn't relate to the trade-offs in resource allocation between individuals.
• Cournot’s Equilibrium: This relates to industrial organization and oligopoly markets, where firms compete on the quantity of output. The equilibrium determines output levels and prices based on firms' strategic choices, not the specific definition of Pareto efficiency.

Therefore, the defining characteristic of a Pareto Optimum aligns directly with the statement provided in the question.