Which of These Is NOT Among the Challenges Facing America

Which of these is NOT among the challenges facing America and Americans in the twenty-first century?

A) The increasingly unequal distribution of wealth
B) Women increasingly surpassing men in the workforce
C) Diminishing oil supplies and the need for alternative energy sources
D) Enhancing national security without eroding civil liberties
E) Protecting the nation's borders without preventing desirable immigrants from coming to the U.S.