Q: 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.
Passage: In November 2004, following a period of turmoil caused by the revelation that Shell had been overstating its oil reserves, it was announced that the Shell Group would move to a single capital structure, creating a new parent company to be named Royal Dutch Shell plc, with its primary listing on the London Stock Exchange, a secondary listing on the Amsterdam Stock Exchange, its headquarters and tax residency in The Hague, Netherlands and its registered office in London. The unification was completed on 20 July 2005 and the original owners delisted their companies from the respective exchanges. On 20 July 2005, the Shell Transport & Trading Company plc was delisted from the LSE, where as, Royal Dutch Petroleum Company from NYSE on 18 November 2005. The shares of the company were issued at a 60/40 advantage for the shareholders of Royal Dutch in line with the original ownership of the Shell Group.
A:
When was it discovered Shell had been overstating its oil reserves?