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.
Example: Passage: In 1763, Spain traded Florida to the Kingdom of Great Britain for control of Havana, Cuba, which had been captured by the British during the Seven Years' War. It was part of a large expansion of British territory following the country's victory in the Seven Years' War. Almost the entire Spanish population left, taking along most of the remaining indigenous population to Cuba. The British soon constructed the King's Road connecting St. Augustine to Georgia. The road crossed the St. Johns River at a narrow point, which the Seminole called Wacca Pilatka and the British named "Cow Ford", both names ostensibly reflecting the fact that cattle were brought across the river there.
Example solution: Who owned Cuba after the Eight Years War?
Example explanation: This question appears to be relevant to the passage as both involves words such as 'Cuba' and 'War' which also exist in the passage. The passage mentions that "after the war, almost the entire Spanish population left, taking along most of the remaining indigenous population to Cuba". This information is not sufficient to conclude that which country owned cuba.

Problem: Passage: BBC TV was renamed BBC1 in 1964, after the launch of BBC2 (now BBC Two), the third television station (ITV was the second) for the UK; its remit, to provide more niche programming. The channel was due to launch on 20 April 1964, but was put off the air by a massive power failure that affected much of London, caused by a fire at Battersea Power Station. A videotape made on the opening night was rediscovered in 2003 by a BBC technician. In the end the launch went ahead the following night, hosted by Denis Tuohy holding a candle. BBC2 was the first British channel to use UHF and 625-line pictures, giving higher definition than the existing VHF 405-line system.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Solution: What channel was launched that caused BBC TV to be renamed BBC2?