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: The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA) is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the colour of its cover. The format is a two-channel 16-bit PCM encoding at a 44.1 kHz sampling rate per channel. Four-channel sound was to be an allowable option within the Red Book format, but has never been implemented. Monaural audio has no existing standard on a Red Book CD; thus, mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono); an MP3 CD, however, can have audio file formats with mono sound.

A: What was the sampling rate for the four-channel sound?
****
Q: Passage: Ann Arbor is a major scene of college sports, most notably at the University of Michigan, a member of the Big Ten Conference. Several well-known college sports facilities exist in the city, including Michigan Stadium, the largest American football stadium in the world. The stadium was completed in 1927 and cost more than $950,000 to build. It has a 109,901 seating capacity after multiple renovations were made. The stadium is colloquially known as "The Big House". Crisler Center and Yost Ice Arena play host to the school's basketball (both men's and women's) and ice hockey teams, respectively. Concordia University, a member of the NAIA, also fields sports teams.

A: What stadium was completed in 1972?
****
Q: Passage: Bermuda's pink sand beaches and clear, cerulean blue ocean waters are popular with tourists. Many of Bermuda's hotels are located along the south shore of the island. In addition to its beaches, there are a number of sightseeing attractions. Historic St George's is a designated World Heritage Site. Scuba divers can explore numerous wrecks and coral reefs in relatively shallow water (typically 30–40 ft or 9–12 m in depth), with virtually unlimited visibility. Many nearby reefs are readily accessible from shore by snorkellers, especially at Church Bay.

A:
What are located along the shore of the coral reefs?
****