Explanation:
The correct answer is option 'B', which is 5 years.

Reasoning:
The Agricultural Census in India is conducted by the Ministry of Agriculture every 5 years in collaboration with the states and Union Territories (UTs). This census has been carried out since 1970 as a part of the World Agriculture Census Programme.

Importance of Agricultural Census:
The Agricultural Census is an essential exercise for gathering comprehensive and accurate data on various aspects of agriculture in the country. It helps in monitoring and evaluating the performance of the agricultural sector and formulating effective policies for its growth and development.

Key Features of Agricultural Census:
1. Conducted by Ministry of Agriculture: The Ministry of Agriculture is responsible for organizing and conducting the Agricultural Census in India. It coordinates with the states and UTs to ensure the smooth implementation of the census.

2. Frequency: The Agricultural Census is carried out every 5 years, providing periodic data on the changing trends and patterns in agriculture. This allows for timely analysis and decision-making by policymakers.

3. Participation of States and UTs: The census involves the active participation of all states and UTs in the country. They contribute to data collection, verification, and reporting processes, ensuring comprehensive coverage and accuracy.

4. World Agriculture Census Programme: The Agricultural Census in India is conducted as a part of the World Agriculture Census Programme. This global initiative aims to standardize agricultural data collection methods and promote data comparability across countries.

5. Data Collection and Analysis: The Agricultural Census collects information on various aspects of agriculture, including land use, cropping patterns, irrigation facilities, livestock population, machinery, and agricultural practices. This data is then analyzed to generate valuable insights into the state of agriculture in the country.

6. Policy Formulation: The data obtained from the Agricultural Census plays a crucial role in policy formulation and decision-making. It helps policymakers identify challenges, formulate strategies, and allocate resources effectively to promote agricultural growth and enhance farmers' welfare.

In conclusion, the Agricultural Census is conducted by the Ministry of Agriculture every 5 years with the participation of states and UTs since 1970. This exercise provides vital data on agriculture, enabling policymakers to make informed decisions and promote the development of the agricultural sector in the country.