Primary industry refers to the activities that are connected with the extraction and production of natural resources and reproduction and development of living organisms. It is the first stage of the economic activity chain and plays a crucial role in providing raw materials for other industries. Here is a detailed explanation of why the correct answer is option 'A':

1. Definition of Primary Industry:
- Primary industry, also known as the primary sector, involves activities that directly extract or harvest natural resources from the earth or grow and develop living organisms.
- It includes sectors such as agriculture, forestry, fishing, mining, and quarrying.
- These activities are considered the foundation of any economy as they provide the basic materials and resources needed for other industries to function.

2. Extraction and Production of Natural Resources:
- Primary industry encompasses activities related to the extraction and production of natural resources, such as minerals, oil, gas, coal, metals, and other raw materials.
- Mining and quarrying involve the extraction of minerals from the earth's crust, while oil and gas extraction involve drilling and extracting hydrocarbon resources.
- Agriculture is another significant component of primary industry, involving the cultivation of crops and the rearing of livestock for food production.

3. Reproduction and Development of Living Organisms:
- Primary industry also includes activities related to the reproduction and development of living organisms.
- This involves agricultural practices, such as breeding livestock, poultry farming, and fish farming, to produce food resources.
- Forestry is another aspect of primary industry that involves the cultivation and management of forests for timber and other forest products.

4. Importance of Primary Industry:
- Primary industry forms the backbone of an economy by providing the essential raw materials needed for manufacturing and production in secondary and tertiary industries.
- It contributes to job creation, income generation, and overall economic development.
- Primary industry also has a significant impact on the environment and requires sustainable practices to ensure the conservation of natural resources.

In conclusion, primary industry encompasses activities related to the extraction and production of natural resources as well as the reproduction and development of living organisms. It is a vital sector that provides the raw materials needed for other industries and plays a fundamental role in economic growth and development.