In the context of Indian economic policy, the concept of a joint sector specifically refers to cooperation between which types of enterprises?

Introduction / Context:
The idea of a joint sector has been discussed in Indian planning and industrial policy since the middle of the twentieth century. It represents a particular organisational form where both government owned and privately owned enterprises participate together in ownership and management. This question checks whether you know which parties are involved in such a joint sector arrangement.

Given Data / Assumptions:

• The term used is joint sector.
• Options describe different types of cooperation: public private, inter governmental, and domestic foreign.
• The context is clearly Indian economic planning.

Concept / Approach:
Joint sector in Indian policy literature refers to enterprises where the government, typically through public sector units or financial institutions, holds a significant part of the equity and participates in management, while private investors hold the remaining part and also participate in running the enterprise. It was seen as a middle path between full state ownership and purely private ownership, combining benefits of both sectors.

Step-by-Step Solution:
Step 1: Recognise that joint sector is a term used in discussions of mixed economy and public private partnership.Step 2: Recall that in such enterprises both public and private shareholders are present.Step 3: State and central government cooperation describes inter governmental relations, not joint sector in the sense of industrial ownership.Step 4: Domestic and foreign company collaboration is usually described as joint ventures or foreign direct investment rather than joint sector.Step 5: Therefore, joint sector means cooperation between public sector and private sector industries.

Verification / Alternative Check:
Indian planning commission documents and textbooks on Indian economy describe joint sector units as enterprises where government and private interests jointly own and operate the company. Examples include some heavy engineering and infrastructure projects where the state wanted control but also wanted private capital and expertise. The definition consistently focuses on public private participation rather than any other pairing.

Why Other Options Are Wrong:
Cooperation between state and central governments is important but falls under federal relations, not joint sector industrial organisation. Links between domestic and foreign companies are typically labelled joint ventures, strategic alliances or foreign collaborations, and are not the intended meaning of joint sector in this question. Option D and option E are too broad and do not match the specific policy usage of the term.

Common Pitfalls:
Some candidates may confuse joint sector with any joint venture, including foreign partners, because of the word joint. Others may think of coordination between levels of government. To avoid confusion, always remember that in the Indian mixed economy context, joint sector has a specific meaning: enterprises jointly owned and managed by the public sector and private sector.

Final Answer:
The concept of joint sector in Indian planning refers to cooperation between public sector and private sector industries.