Kakrapar Atomic Energy Station is located in the state of ______.

The correct answer is D, The North Atlantic Treaty Organization. NATO is the military alliance of European and North American states, formed by the North Atlantic Treaty signed at Washington on 4 April 1949 by twelve founding members, and its membership has grown in rounds since then. Its headquarters is at Brussels in Belgium, and Article 5 of the treaty is its core promise: an armed attack on one member is treated as an attack on all. Note that the paper's figure of 30 members belongs to the year the question was set, as the alliance has admitted more states since. Options A, B and C name no real body; they are invented labels built from military-sounding words, and none of them appears in any list of international organisations. A useful contrast is the Warsaw Pact of 1955, the Soviet-led bloc that stood against NATO until it dissolved in 1991. Exam tip: NATO — treaty signed 4 April 1949 at Washington, headquarters Brussels, Article 5 for collective defence.

The correct answer is B, Chittaranjan Das. C. R. Das was the Calcutta barrister who defended Aurobindo Ghosh in the Alipore bomb case, gave up a large practice for the non-cooperation movement, and founded the Swaraj Party with Motilal Nehru to contest the legislative councils. Bengal called him Deshbandhu, the friend of the nation, and Kolkata's Deshbandhu Park and college keep the name.

Option A, Rajendra Prasad, the first President of India, is Deshratna, the jewel of the nation, which is the neatest trap in this set. Option C, Jayaprakash Narayan, is Loknayak, the leader of the people. Option D, Madan Mohan Malaviya, the founder of Banaras Hindu University, is Mahamana. All four titles are genuine, so this question is decided by the exact pairing.

The correct answer is A, Milkha Singh. Milkha Singh was a sprinter who won the four hundred metres gold at the Commonwealth Games of 1958 and at the Asian Games, and who finished fourth in the four hundred metres final at the Rome Olympics of 1960. The name Flying Sikh is said to have been given to him in Pakistan after he won a race there, and it has stayed with him.

Option B, Gurbachan Singh Randhawa, was a decathlete and hurdler who also reached an Olympic final for India. Option C, Balbir Singh Senior, was the hockey centre forward of three Olympic gold medal teams. Option D, Ajit Pal Singh, captained the Indian hockey team that won the World Cup in 1975. Three of the four are hockey players, so the clue is that the Flying Sikh was an athlete on the track.

The correct answer is B, Verghese Kurien. Kurien built the cooperative dairy at Anand in Gujarat, gave the country the Amul brand and headed the National Dairy Development Board, whose Operation Flood turned India into a large milk producer. That work is the White Revolution, and it earned him the name Milkman of India; National Milk Day is observed on his birthday, 26 November.

Option A, M. S. Swaminathan, is called the father of the Green Revolution in India for the high yielding wheat and rice varieties of the nineteen sixties. Option C, Norman Borlaug, was the American agronomist behind the dwarf wheat varieties and is called the father of the Green Revolution worldwide. Option D, Hiralal Chaudhuri, worked on induced breeding of fish and is linked with the Blue Revolution. Each revolution has its own name, which is the test here.

The correct answer is A, Vikram Sarabhai. Sarabhai set up the Physical Research Laboratory at Ahmedabad, persuaded the government that a developing country needed space technology for communication and weather, and built the Thumba Equatorial Rocket Launching Station in Kerala, so he is called the father of the Indian space programme. The Vikram Sarabhai Space Centre at Thiruvananthapuram carries his name.

Option B, C. V. Raman, won the Nobel Prize in Physics in 1930 for the scattering of light, and National Science Day marks the day of his discovery. Option C, Meghnad Saha, gave the ionisation equation used in the study of stellar spectra. Option D, Jagadish Chandra Bose, worked on radio waves and on plant response. Each is a great Indian scientist, but only Sarabhai is tied to the space programme.