Which nation has threatened world security in recent years because of its interest in becoming a nuclear power? north korea venezuela vietnam iraq

North Korea

Explanation:

North Korea is the country that has threatened world security in recent years because of its interest in becoming a nuclear power.  Its leader wants to impose himself as a world figure and uses the threat of nuclear weapon as a bargaining chip.

Venezuela : The country is on the verge of a civil war, totally collapsed, not a threat to the world, but to its people yes.

Vietnam: No major conflict happening there now, and certainly not an emerging nuclear power.

Iraq: still recovering from wars... not a nuclear threat.