In economic theory, a mixed economy refers to a system characterised by which of the following features?

Introduction / Context:
This conceptual question from economics tests understanding of the term mixed economy. Many countries, including India, describe their economic system as a mixed economy, so it is important to know what mixture the term refers to.

Given Data / Assumptions:

• The subject is an economic system, not regional geography or social structure.
• The question asks what a mixed economy denotes.
• Options describe different kinds of coexistence between sectors or regions.
• We assume the standard textbook meaning of mixed economy.

Concept / Approach:
A mixed economy combines elements of both capitalism and socialism. In practical terms, this means a coexistence of private enterprise and public or state owned enterprise in the production and distribution of goods and services. The state regulates markets and directly participates in key sectors, while private businesses operate in other areas. Therefore the correct answer is the coexistence of private and public sectors.

Step-by-Step Solution:
Step 1: Recall the basic definition of a mixed economy as a blend of market and planning elements.Step 2: Identify that this blend usually takes the form of both private sector and public sector participation.Step 3: Examine the options for the one that reflects this coexistence.Step 4: Option B explicitly describes coexistence of private and public sectors.Step 5: Select this option as the correct answer.

Verification / Alternative check:
Economic textbooks define mixed economy as an economic system in which both private and public sectors coexist and interact. They often cite countries like India, the United Kingdom and others as examples, where government owned enterprises operate alongside private firms. This consistent definition confirms that the key feature is the coexistence of these two types of ownership, not merely rural and urban areas or different regions.

Why Other Options Are Wrong:
Coexistence of rural and urban sectors is present in almost all economies, whether capitalist, socialist or mixed, so it does not uniquely define a mixed economy.
Coexistence of only heavy and small industries describes industrial structure, not the nature of ownership or control.
Coexistence of developed and underdeveloped regions refers to regional imbalance and again is not unique to mixed economies.
Complete absence of state intervention would describe a pure free market economy, which is the opposite of the mixed economy idea.

Common Pitfalls:
Candidates sometimes confuse mixed economy with structural diversity, such as having both agriculture and industry. Others may focus on regional disparities or think that mixed refers to a mix of rich and poor areas. The vital point is that mixed relates to the mix of ownership and control between public and private sectors. Keeping this in mind makes the concept easy to recall.

Final Answer:
A mixed economy is characterised by the coexistence of private and public sectors within the same economic system.