Detailed Instructions: In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.
Q: Passage: The One Hundred Eleventh United States Congress was a meeting of the legislative branch of the United States federal government from January 3, 2009, until January 3, 2011. It began during the last two weeks of the George W. Bush administration, with the remainder spanning the first two years of Barack Obama's presidency. It was composed of the Senate and the House of Representatives. The apportionment of seats in the House was based on the 2000 U.S. Census. In the November 4, 2008 elections, the Democratic Party increased its majorities in both chambers, giving President Obama a Democratic majority in the legislature for the first two years of his presidency. A new delegate seat was created for the Northern Mariana Islands. The 111th Congress had the most experienced members in history: at the start of the 111th Congress, the average member of the House had served 10.3 years, while the average Senator had served 13.4 years.
Link Information: The Northern Mariana Islands came under U.S. sovereignty on November 4, 1986 Answer: November 4, 1986
A:
When did the Northern Mariana Islands become a territory of the United States?