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.

[Q]: Passage: For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach all of this data would be placed in a single record, and unused items would simply not be placed in the database. In the relational approach, the data would be normalized into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided.
[A]: How is a database system rarely used?

[Q]: Passage: The United States Mint produces Proof Sets specifically for collectors and speculators. Silver Proofs tend to be the standard designs but with the dime, quarter, and half dollar containing 90% silver. Starting in 1983 and ending in 1997, the Mint also produced proof sets containing the year's commemorative coins alongside the regular coins. Another type of proof set is the Presidential Dollar Proof Set where four special $1 coins are minted each year featuring a president. Because of budget constraints and increasing stockpiles of these relatively unpopular coins, the production of new Presidential dollar coins for circulation was suspended on December 13, 2011, by U.S. Treasury Secretary Timothy F. Geithner. Future minting of such coins will be made solely for collectors.
[A]: What is specifically produced for budget constraints?

[Q]: Passage: Myocardial infarction (MI) or acute myocardial infarction (AMI), commonly known as a heart attack, occurs when blood flow stops to a part of the heart causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck, or jaw. Often it is in the center or left side of the chest and lasts for more than a few minutes. The discomfort may occasionally feel like heartburn. Other symptoms may include shortness of breath, nausea, feeling faint, a cold sweat, or feeling tired. About 30% of people have atypical symptoms, with women more likely than men to present atypically. Among those over 75 years old, about 5% have had an MI with little or no history of symptoms. An MI may cause heart failure, an irregular heartbeat, or cardiac arrest.
[A]:
What is the scientific name for blood flow?