This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Ex Input:
Passage: Machine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more widespread. Barcode scanners are the most common example of machine vision, and many low cost products use red LEDs instead of lasers. Optical computer mice are an example of LEDs in machine vision, as it is used to provide an even light source on the surface for the miniature camera within the mouse. LEDs constitute a nearly ideal light source for machine vision systems for several reasons:

Ex Output:
 non-LEDs are often used for what type of systems?


Ex Input:
Passage: In the floor, just inside the great west door, in the centre of the nave, is the tomb of The Unknown Warrior, an unidentified British soldier killed on a European battlefield during the First World War. He was buried in the abbey on 11 November 1920. This grave is the only one in the abbey on which it is forbidden to walk.[citation needed]

Ex Output:
When was The Known Warrior buried?


Ex Input:
Passage: The dry lands of Namibia were inhabited since early times by San, Damara, and Namaqua, and since about the 14th century AD by immigrating Bantu who came with the Bantu expansion. Most of the territory became a German Imperial protectorate in 1884 and remained a German colony until the end of World War I. In 1920, the League of Nations mandated the country to South Africa, which imposed its laws and, from 1948, its apartheid policy. The port of Walvis Bay and the offshore Penguin Islands had been annexed by the Cape Colony under the British crown by 1878 and had become an integral part of the new Union of South Africa at its creation in 1910.

Ex Output:

Where did the Bantu come from in the 14th century?