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: Uranium was also used in photographic chemicals (especially uranium nitrate as a toner), in lamp filaments for stage lighting bulbs, to improve the appearance of dentures, and in the leather and wood industries for stains and dyes. Uranium salts are mordants of silk or wool. Uranyl acetate and uranyl formate are used as electron-dense "stains" in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.

Ex Output:
What product of uranium wasn't used as toner?


Ex Input:
Passage: Since about the year 2000, a growing number of Internet pharmacies have been established worldwide. Many of these pharmacies are similar to community pharmacies, and in fact, many of them are actually operated by brick-and-mortar community pharmacies that serve consumers online and those that walk in their door. The primary difference is the method by which the medications are requested and received. Some customers consider this to be more convenient and private method rather than traveling to a community drugstore where another customer might overhear about the drugs that they take. Internet pharmacies (also known as online pharmacies) are also recommended to some patients by their physicians if they are homebound.

Ex Output:
When did internet pharmacies begin to end?


Ex Input:
Passage: This contrasts with the presidential system, in which the president (or equivalent) is both the head of state and the head of the government. In some presidential or semi-presidential systems, such as those of France, Russia or South Korea, the prime minister is an official generally appointed by the president but usually approved by the legislature and responsible for carrying out the directives of the president and managing the civil service. The head of government of the People's Republic of China is referred to as the Premier of the State Council and the premier of the Republic of China (Taiwan) is also appointed by the president, but requires no approval by the legislature.

Ex Output:

Who is both head of state and the head of government in France?