The Sonepur fair, described as the largest cattle fair of Asia, is held at the confluence of which two rivers?

The correct answer is A, 22 March. On 22 March 1912 the province of Bihar and Orissa was carved out of the Bengal Presidency, which gave Bihar a separate administrative identity for the first time. The day is observed every year as Bihar Diwas with cultural programmes in the state and among people from Bihar living elsewhere.

Option B, 15 November, is the day Jharkhand was created out of the southern districts of Bihar in 2000, and is observed as Jharkhand's formation day. Option C, 1 November, is the formation day of several states created by the States Reorganisation Act of 1956, among them Karnataka, Kerala, Madhya Pradesh and Andhra Pradesh. Option D, 26 January, is Republic Day and belongs to the nation, not to any single state.

The correct answer is C, 2000. Jharkhand was created on 15 November 2000, the birth anniversary of Birsa Munda, out of the southern plateau districts of Bihar. It was one of three states formed that year, along with Chhattisgarh out of Madhya Pradesh and Uttaranchal, now Uttarakhand, out of Uttar Pradesh. The separation took away most of Bihar's coal, iron ore and heavy industry.

Option A, 1956, is the year of the States Reorganisation Act, which redrew boundaries on linguistic lines but did not create Jharkhand. Option B, 1972, is the year Meghalaya, Manipur and Tripura became full states. Option D, 2014, is the year Telangana was separated from Andhra Pradesh, and it is the commonest wrong choice for candidates who remember only that a state was created that year.

The correct answer is B, Kosi. The Kosi rises in Nepal, carries an enormous load of Himalayan silt and keeps raising its own bed, so it spills over and abandons its channel again and again. It has shifted its course far to the west over the last two centuries and floods a wide belt of northern Bihar almost every year, which is how it earned the name.

Option A, the Sone, joins the Ganga from the south and is the largest southern tributary in the state; it does not behave in this way. Option C, the Falgu, flows past Gaya and is famous for the Pitrapaksha rites rather than for floods. Option D, the Punpun, is another southern river of the Ganga basin. Note the parallel names asked in the same papers: the Damodar is the Sorrow of Bengal and the Hwang Ho the Sorrow of China.

The correct answer is A, Valmiki National Park. It lies in the West Champaran district on the border with Nepal, in the basin of the Gandak, and forms the core of the Valmiki Tiger Reserve, the only tiger reserve of the state. Its forests are the eastern end of the Himalayan foothill belt and hold tiger, leopard, sloth bear and a rich bird life.

Option B, Betla National Park, is in the Palamu district of Jharkhand, which was part of Bihar until 2000, and it is the commonest wrong answer for this reason. Option C, Dudhwa National Park, is in Uttar Pradesh on the same Nepal border, which makes it a natural confusion. Option D, Kanha National Park, is in Madhya Pradesh and is far from the region altogether.

The correct answer is B, Bodh Gaya. The Buddha attained enlightenment under the bodhi tree on the bank of the Falgu at Bodh Gaya in the Gaya district. The Mahabodhi Temple Complex that stands there is inscribed on the UNESCO World Heritage List and is the most visited Buddhist site in India.

Option A, Sarnath, near Varanasi in Uttar Pradesh, is where he preached his first sermon, and its Lion Capital gave India its State Emblem. Option C, Kushinagar, also in Uttar Pradesh, is where he attained mahaparinirvana. Option D, Lumbini, in Nepal, is his birthplace. The four sites are asked together as a set, so fix them in that order: birth at Lumbini, enlightenment at Bodh Gaya, first sermon at Sarnath and death at Kushinagar.