Question: How many countries comprise the region that includes a country where North Sea oil was discovered in the 1970s?

Context paragraphs:
Countries of the United Kingdom: The United Kingdom (UK) comprises four countries: England, Scotland, Wales and Northern Ireland.

Sea Quest: The Sea Quest was a semi-submersible drilling rig.  She discovered the UK's first North Sea oil on 14 September 1969 in the Arbroath Field.  She also discovered the first giant oil field named Forties on 7 October 1970.

Death of Bradley Westell: Bradley Westell was a British commercial diver who died on 31 July 1995 in the North Sea off Bacton, Norfolk after his umbilical was dragged into one of the thrusters of the diving support vessel "Stena Orelia".  The accident led to the 1997 conviction of diving supervisor Kenneth Roberts for perverting the course of justice.  Roberts received the first prison sentence ever given for a crime committed offshore by a person working in the North Sea oil industry.

Ekofisk oil field: Ekofisk is an oil field in block 2/4 of the Norwegian sector of the North Sea about 320 km southwest of Stavanger.  Discovered in 1969 by Phillips Petroleum Company, it remains one of the most important oil fields in the North Sea.  This was the first discovery of oil after the drilling of over 200 exploration wells in the North Sea "triggered" by the Groningen gas field discovery.  In 1971, Phillips started producing directly to tankers from four subsea wells.  Oil production is planned to continue until at least 2050.

Barryroe: Barryroe is an oil and gas field discovered in the Celtic Sea due south of Cork.  Close to the exhausted Kinsale Head gas field, it is as close as 3 km to the Kinsale Head existing pipeline.  The discovery is at a water depth of 100 m .  Several attempts were made to find a commercial field at the site in the 1970s but although they struck oil, none were commercially viable.  It has been rated as the equivalent of a large North Sea oil field.

Energy in Norway: Since the discovery of North Sea oil in Norwegian waters during the late 1960s, exports of oil and gas have become very important elements of the economy of Norway.  With North Sea oil production having peaked, disagreements over exploration for oil in the Barents Sea, the prospect of exploration in the Arctic, as well as growing international concern over global warming, energy in Norway is currently receiving close attention.

Economic history of Scotland: The economic history of Scotland charts economic development in the history of Scotland from earliest times, through seven centuries as an independent state and following Union with England, three centuries as a country of the United Kingdom.  Before 1700 Scotland was a poor rural area, with few natural resources or advantages, remotely located on the periphery of the European world.  Outward migration to England, and to North America, was heavy from 1700 well into the 20th century.  After 1800 the economy took off, and industrialized rapidly, with textile, coal, iron, railroads, and most famously shipbuilding and banking.  Glasgow was the centre of the Scottish economy.  After the end of the First World War in 1918, Scotland went into a steady economic decline, shedding thousands of high-paying engineering jobs, and having very high rates of unemployment especially in the 1930s.  Wartime demand in the Second World War temporarily reversed the decline, but conditions were difficult in the 1950s and 1960s.  The discovery of North Sea oil in the 1970s brought new wealth, and a new cycle of boom and bust, even as the old industrial base had decayed.

It's Scotland's oil: "It's Scotland's oil" was a widely publicised political slogan used by the Scottish National Party (SNP) during the 1970s in making their economic case for Scottish independence.  It was argued that the discovery of North Sea oil off the coast of Scotland, and the revenue that it created would not benefit Scotland to any significant degree while Scotland remained part of the United Kingdom.

North Sea oil: North Sea oil is a mixture of hydrocarbons, comprising liquid petroleum and natural gas, produced from petroleum reservoirs beneath the North Sea.

List of oil and gas fields of the North Sea: This list of oil and gas fields of the North Sea contains links to oil and natural gas reservoirs beneath the North Sea.  In terms of the oil industry, "North Sea oil" often refers to a larger geographical set, including areas such as the Norwegian Sea and the UK "Atlantic Margin" (west of Shetland) which are not, strictly speaking, part of the North Sea.

Supporting paragraphs: Economic history of Scotland Countries of the United Kingdom
Answer: four countries