In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.

The G20, or Group of Twenty, is an international forum which (1) _______19 countries and the European Union (EU). It focuses on significant global economic challenges such as international financial (2) ________, climate change mitigation, and (3) __________ development. In 1999, the G20 was formed in (4) _________ to various global economic crises. The G20 (5) __________ itself the principal arena for international economic and financial cooperation during its 2009 meeting.