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.
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Question: Passage: The City of Charleston Fire Department consists over 300 full-time firefighters. These firefighters operate out of 19 companies located throughout the city: 16 engine companies, two tower companies, and one ladder company. Training, Fire Marshall, Operations, and Administration are the divisions of the department. The department operates on a 24/48 schedule and had a Class 1 ISO rating until late 2008, when ISO officially lowered it to Class 3. Russell (Rusty) Thomas served as Fire Chief until June 2008, and was succeeded by Chief Thomas Carr in November 2008.

Answer: How many companies aren't there in the City of Charleston Fire Department?

Question: Passage: The service started on 1 September 1993 based on the idea from the then chief executive officer, Sam Chisholm and Rupert Murdoch, of converting the company business strategy to an entirely fee-based concept. The new package included four channels formerly available free-to-air, broadcasting on Astra's satellites, as well as introducing new channels. The service continued until the closure of BSkyB's analogue service on 27 September 2001, due to the launch and expansion of the Sky Digital platform. Some of the channels did broadcast either in the clear or soft encrypted (whereby a Videocrypt decoder was required to decode, without a subscription card) prior to their addition to the Sky Multichannels package. Within two months of the launch, BSkyB gained 400,000 new subscribers, with the majority taking at least one premium channel as well, which helped BSkyB reach 3.5 million households by mid-1994. Michael Grade criticized the operations in front of the Select Committee on National Heritage, mainly for the lack of original programming on many of the new channels.

Answer: What platform helped BSkyB to avoid ending their analogue service?

Question: Passage: Thrombolysis involves the administration of medication that activates the enzymes that normally destroy blood clots. Thrombolysis agents include streptokinase, reteplase, alteplase, and tenecteplase. If no contraindications are present (such as a high risk of bleeding), thrombolysis can be given in the pre-hospital or in-hospital setting. When given to people suspected of having a STEMI within 6 hours of the onset of symptoms, thrombolytic drugs save the life of 1 in 43 who received them. The risks were major bleeding (1 in 143) and brain bleeding (1 in 250). It is unclear whether pre-hospital thrombolysis reduces death in people with STEMI compared to in-hospital thrombolysis. Pre-hospital thrombolysis reduces time to thrombolytic treatment, based on studies conducted in higher income countries.

Answer:
What enzymes in the body typically destroy blood clots?