TASK DEFINITION: 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.
PROBLEM: Passage: SVCD has two-thirds the resolution of DVD, and over 2.7 times the resolution of VCD. One CD-R disc can hold up to 60 minutes of standard quality SVCD-format video. While no specific limit on SVCD video length is mandated by the specification, one must lower the video bit rate, and therefore quality, to accommodate very long videos. It is usually difficult to fit much more than 100 minutes of video onto one SVCD without incurring significant quality loss, and many hardware players are unable to play video with an instantaneous bit rate lower than 300 to 600 kilobits per second.

SOLUTION: How much can a VCD hold?

PROBLEM: Passage: In 1872, Russian Alexander Lodygin invented an incandescent light bulb and obtained a Russian patent in 1874. He used as a burner two carbon rods of diminished section in a glass receiver, hermetically sealed, and filled with nitrogen, electrically arranged so that the current could be passed to the second carbon when the first had been consumed. Later he lived in the USA, changed his name to Alexander de Lodyguine and applied and obtained patents for incandescent lamps having chromium, iridium, rhodium, ruthenium, osmium, molybdenum and tungsten filaments, and a bulb using a molybdenum filament was demonstrated at the world fair of 1900 in Paris.

SOLUTION: Who did not patent an incandescent light bulb in 1872?

PROBLEM: Passage: In 1939 East Prussia had 2.49 million inhabitants, 85% of them ethnic Germans, the others Poles in the south who, according to Polish estimates numbered in the interwar period around 300,000-350,000, the Latvian speaking Kursenieki, and Lietuvininkai who spoke Lithuanian in the northeast. Most German East Prussians, Masurians, Kursieniki, and Lietuvininkai were Lutheran, while the population of Ermland was mainly Roman Catholic due to the history of its bishopric. The East Prussian Jewish Congregation declined from about 9,000 in 1933 to 3,000 in 1939, as most fled from Nazi rule. Those who remained were later deported and killed in the Holocaust.

SOLUTION:
How many Latvian speaking Kursenieki were there?