The correct answer is (a) Civil nuclear cooperation.
India and Russia have a long history of cooperation in the civil nuclear sector. In 2008, the two countries signed a landmark agreement on civil nuclear cooperation, which paved the way for the construction of two nuclear power plants in India by Russia. The agreement also includes cooperation in the areas of nuclear fuel supply, safety, and research and development.
The agreement on civil nuclear cooperation is a major milestone in the relationship between India and Russia. It will help to strengthen the two countries’ strategic partnership and promote economic development in both countries.
The other options are incorrect because they do not reflect the main focus of the agreement between India and Russia. Option (b), climate change, is an important issue that is being addressed by both countries, but it is not the main focus of the agreement. Option (c), cooperation in agriculture sector, is an area of cooperation between India and Russia, but it is not the main focus of the agreement. Option (d), cooperation in science and technology sector, is an area of cooperation between India and Russia, but it is not the main focus of the agreement.