TASK DEFINITION: This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
PROBLEM: Passage: After a new wave of UN sanctions, on 11 March 2013, North Korea claimed that it had invalidated the 1953 armistice. On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression". On 30 March 2013, North Korea stated that it had entered a "state of war" with South Korea and declared that "The long-standing situation of the Korean peninsula being neither at peace nor at war is finally over". Speaking on 4 April 2013, the U.S. Secretary of Defense, Chuck Hagel, informed the press that Pyongyang had "formally informed" the Pentagon that it had "ratified" the potential usage of a nuclear weapon against South Korea, Japan and the United States of America, including Guam and Hawaii. Hagel also stated that the United States would deploy the Terminal High Altitude Area Defense anti-ballistic missile system to Guam, because of a credible and realistic nuclear threat from North Korea. Question: How does the United States view North Korea's threats?

SOLUTION: credible and realistic nuclear threat

PROBLEM: Passage: The UAP had been formed as a new conservative alliance in 1931, with Labor defector Joseph Lyons as its leader. The stance of Lyons and other Labor rebels against the more radical proposals of the Labor movement to deal the Great Depression had attracted the support of prominent Australian conservatives. With Australia still suffering the effects of the Great Depression, the newly formed party won a landslide victory at the 1931 Election, and the Lyons Government went on to win three consecutive elections. It largely avoided Keynesian pump-priming and pursued a more conservative fiscal policy of debt reduction and balanced budgets as a means of stewarding Australia out of the Depression. Lyons' death in 1939 saw Robert Menzies assume the Prime Ministership on the eve of war. Menzies served as Prime Minister from 1939 to 1941 but resigned as leader of the minority World War II government amidst an unworkable parliamentary majority. The UAP, led by Billy Hughes, disintegrated after suffering a heavy defeat in the 1943 election. Question: What years did Robert Menzies serve as Prime Minister?

SOLUTION: 1939 to 1941

PROBLEM: Passage: In 2008, Bloomberg claimed child labour in copper and cobalt mines that supplied Chinese companies in Congo. The children are creuseurs, that is they dig the ore by hand, carry sacks of ores on their backs, and these are then purchased by these companies. Over 60 of Katanga's 75 processing plants are owned by Chinese companies and 90 percent of the region's minerals go to China. An African NGO report claimed 80,000 child labourers under the age of 15, or about 40% of all miners, were supplying ore to Chinese companies in this African region. Amnesty International alleged in 2016 that some cobalt sold by Congo Dongfang Mining was produced by child labor, and that it was being used in lithium-ion batteries powering electric cars and mobile devices worldwide. Question: What is the cobalt used for?

SOLUTION:
lithium-ion batteries powering electric cars and mobile devices worldwide