Why is the NAIRU in most European countries so much hiogher than in the U.S.? a. European countries have usually failed to shield their workers from foreign competition and dumping b. Most Europe labor markets are very flexible and European labor market policies have tended to over promote "churn" c. European countries have experienced very rapid technological change that has destroyed jobs d. There is too little "churn" in Europe due to European labor markets policies that seek to prevent job losses e. European countries have had too much "churn" compared to the U.S