The question asks to identify the nation that announced its withdrawal from the Organization of the Petroleum Exporting Countries (OPEC) in October 2019, with the withdrawal effective from January 1, 2020.
Based on the announcement made in October 2019, the country that decided to leave OPEC effective January 1, 2020, was Ecuador.
Ecuador was the nation that announced its withdrawal from OPEC in October 2019.
The Chagos Archipelago, recently in the news, is a disputed territory between which two countries?