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.

Example Input: Passage: Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties.
Example Output: What can be used to make glass less dense?

Example Input: Passage: The northern side of Miami includes Midtown, a district with a great mix of diversity with many West Indians, Hispanics, European Americans, bohemians, and artists. Edgewater, and Wynwood, are neighborhoods of Midtown and are made up mostly of high-rise residential towers and are home to the Adrienne Arsht Center for the Performing Arts. The wealthier residents usually live in the northeastern part, in Midtown, the Design District, and the Upper East Side, with many sought after 1920s homes and home of the MiMo Historic District, a style of architecture originated in Miami in the 1950s. The northern side of Miami also has notable African American and Caribbean immigrant communities such as Little Haiti, Overtown (home of the Lyric Theater), and Liberty City.
Example Output: What unnotable theater is present in Overtown?

Example Input: Passage: Möngke Khan commenced a military campaign against the Chinese Song dynasty in southern China. The Mongol force that invaded southern China was far greater than the force they sent to invade the Middle East in 1256. He died in 1259 without a successor. Kublai returned from fighting the Song in 1260 when he learned that his brother, Ariq Böke, was challenging his claim to the throne. Kublai convened a kurultai in Kaiping that elected him Great Khan. A rival kurultai in Mongolia proclaimed Ariq Böke Great Khan, beginning a civil war. Kublai depended on the cooperation of his Chinese subjects to ensure that his army received ample resources. He bolstered his popularity among his subjects by modeling his government on the bureaucracy of traditional Chinese dynasties and adopting the Chinese era name of Zhongtong. Ariq Böke was hampered by inadequate supplies and surrendered in 1264. All of the three western khanates (Golden Horde, Chagatai Khanate and Ilkhanate) became functionally autonomous, although only the Ilkhans truly recognized Kublai as Great Khan. Civil strife had permanently divided the Mongol Empire.
Example Output:
 Who led a Mongol defense on the Song dynasty?