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: An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure. Zintl phases are also sometimes considered alloys depending on bond types (see also: Van Arkel-Ketelaar triangle for information on classifying bonding in binary compounds).
[A]: What is always a mixture of metal and other elements?


[Q]: Passage: Photo Gallery is an optional application to view, create and group photos from PS3, which is installed separately from the system software at 105 MB. It was introduced in system software version 2.60 and provides a range of tools for sorting through and displaying the system's pictures. The key feature of this application is that it can organize photos into groups according to various criteria. Notable categorizations are colors, ages, or facial expressions of the people in the photos. Slideshows can be viewed with the application, along with music and playlists. The software was updated with the release of system software version 3.40 allowing users to upload and browse photos on Facebook and Picasa.
[A]: What allows you to view photos on PS4?


[Q]: Passage: In January 2015, a customer named Ricardo Brown received a bill from Comcast with his name changed to "Asshole Brown". Brown's wife, Lisa, believed a Comcast employee changed the name in response to the Browns' request to cancel their cable service, an incident in which she was refused a cancellation unless she paid a $60 fee and instead was routed to a retention specialist. Comcast refused to correct the name on their bill after bringing it to the attention of numerous customer service outlets for the company by explaining that Ricardo is the legal name of the customer, so the Browns turned to consumer advocate Christopher Elliott. Elliott posted the facts of the incident, along with a copy of the bill, on his blog. Shortly thereafter, Elliott contacted Comcast and Comcast offered the Browns an apology, a $60 refund, and a promise to track down and fire the responsible employee. The Browns instead requested a full refund for their negative experience and Comcast agreed to refund the family the last two years of service and provide the next two years of service at no charge. Comcast released a statement explaining: "We have spoken with our customer and apologized for this completely unacceptable and inappropriate name change. We have zero tolerance for this type of disrespectful behavior and are conducting a thorough investigation to determine what happened. We are working with our customer to make this right and will take appropriate steps to prevent this from happening again." 
[A]:
What was the name of the Comcast employee that changed Ricardo's name?