In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Ex Input:
What does every plane have?, Context: Grey-box testing (American spelling: gray-box testing) involves having knowledge of internal data structures and algorithms for purposes of designing tests, while executing those tests at the user, or black-box level. The tester is not required to have full access to the software's source code.[not in citation given] Manipulating input data and formatting output do not qualify as grey-box, because the input and output are clearly outside of the "black box" that we are calling the system under test. This distinction is particularly important when conducting integration testing between two modules of code written by two different developers, where only the interfaces are exposed for test.

Ex Output:
black box


Ex Input:
Why could there be reasonable doubt about the validity of what was stated that she said?, Context: In May 2007, The Daily Telegraph, citing unnamed sources, reported that the Queen was "exasperated and frustrated" by the policies of the British Prime Minister, Tony Blair, that she was concerned the British Armed Forces were overstretched in Iraq and Afghanistan, and that she had raised concerns over rural and countryside issues with Blair. She was, however, said to admire Blair's efforts to achieve peace in Northern Ireland. On 20 March 2008, at the Church of Ireland St Patrick's Cathedral, Armagh, the Queen attended the first Maundy service held outside England and Wales. At the invitation of the Irish President, Mary McAleese, the Queen made the first state visit to the Republic of Ireland by a British monarch in May 2011.

Ex Output:
unnamed sources


Ex Input:
Which came later, victory over Napoleon or the Anglo-Zulu war?, Context: In Britain's "imperial century", victory over Napoleon left Britain without any serious international rival, other than Russia in central Asia. Unchallenged at sea, Britain adopted the role of global policeman, a state of affairs later known as the Pax Britannica, and a foreign policy of "splendid isolation". Alongside the formal control it exerted over its own colonies, Britain's dominant position in world trade meant that it effectively controlled the economies of many nominally independent countries, such as China, Argentina and Siam, which has been generally characterized as "informal empire". Of note during this time was the Anglo-Zulu War, which was fought in 1879 between the British Empire and the Zulu Empire.

Ex Output:
Anglo-Zulu War