A comparison of market equilibrium points before and after a change in an economic variable is known as –

Correct option is B

The correct answer is (B) Comparative statics

Explanation:
• Comparative statics is a method used in economics to analyze how an exogenous change (a change coming from outside the model) affects the equilibrium of a system.
• It involves comparing two different stationary states (equilibria) without considering the path or the time taken to move from the old equilibrium to the new one.
• For instance, if a tax is introduced, an economist would use comparative statics to compare the price and quantity before the tax was implemented with the price and quantity after the market has adjusted to the tax.
• It is 'comparative' because it compares two states and 'static' because it focuses on equilibrium points rather than the dynamic process of movement between them.

Information Booster:
• Alfred Marshall was a key figure in popularizing this approach in microeconomic analysis.
• Dynamic analysis, by contrast, focuses on the 'path' of adjustment over time.
• This method is crucial for predicting the impact of policy changes or shifts in consumer preferences.

Additional Knowledge:
• Demand statics (Option A): This is not a standard economic term; 'statics' usually refers to the equilibrium of the whole system.
• Equilibrium quantity (Option C): This is a specific value (the amount sold) at the point where supply equals demand, not the method of comparison.
• Equilibrium price (Option D): Similar to quantity, this is the specific price point where the market clears.