From the national economic point of view, which one of the following situations best illustrates a microeconomic approach rather than a macroeconomic perspective?

Introduction / Context:
Economics is often divided into microeconomics and macroeconomics. Many exam questions test whether you can correctly classify examples into these two fields. Microeconomics focuses on individual units such as consumers, firms and markets for a specific product, whereas macroeconomics deals with aggregates like national income, total employment, overall price levels and growth rates.

Given Data / Assumptions:

• The question asks for an example that indicates a microeconomic approach.
• Options include topics such as company sales, unemployment, per capita income, inflation and export earnings.
• We assume standard textbook definitions of microeconomics and macroeconomics.

Concept / Approach:
Microeconomics studies the behaviour of individual decision making units: one consumer, one firm, one industry or one commodity market. Macroeconomics studies the economy as a whole, including aggregate demand, national income, aggregate employment and overall price level. Therefore, to identify a microeconomic example, look for a case that deals with a single firm, single market or a specific product rather than nationwide aggregates.

Step-by-Step Solution:
Step 1: Examine each option and decide whether it deals with a specific unit or an aggregate.Step 2: A detailed study of sales of mobile phones by BSNL focuses on a single firm and a specific product market, so it is microeconomic.Step 3: Unemployment among women for the whole country is an aggregate labour market issue, which is macroeconomic.Step 4: Per capita income in India and inflation in India are clearly nationwide aggregates, so they are macroeconomic indicators.Step 5: Total export earnings of the country also represent an aggregate external sector measure, making it macroeconomic as well.

Verification / Alternative check:
A simple test is to ask whether government policies or central banks would normally respond to the variable. If yes, it is probably macroeconomic. For example, inflation and unemployment are classic macro topics managed through fiscal and monetary policy. In contrast, firm level sales performance is studied within microeconomics and business economics and is not itself a macro indicator.

Why Other Options Are Wrong:
Measurement of unemployment among women in the whole country: This deals with overall labour market conditions and is macroeconomic.
Calculation of per capita income in India over a year: Per capita income is a macroeconomic indicator of national income and average living standards.
Analysis of the general inflation rate in India: Inflation is an economy wide phenomenon affecting the overall price level, so it belongs to macroeconomics.
Estimation of total export earnings of the country: Total exports are a macroeconomic measure of the external sector, not a single market or firm.

Common Pitfalls:
Students sometimes assume that any issue involving individuals, such as women or workers, must be microeconomic, but if the focus is on the nationwide aggregate number, it becomes macroeconomic. Always read the scope carefully: one firm or one market suggests micro, while national totals suggest macro. Practising with more examples helps strengthen this classification skill for exam questions.

Final Answer:
The option that illustrates a microeconomic approach is the detailed study of sales of mobile phones by a single company such as BSNL.