Friedman's concept of a flat world means that

Friedman's concept of a flat world means that
 
  a. global warming is destroying the glaciers of the arctic.
  b. economic and informational competition is open globally.
  c. the environmental crisis has resulted in the loss of all major rain forests.
  d. all of these

---

According to Thomas Friedman, which event was a critical step in opening up communication among nations long separated?
 
  a. the breakup of the former Soviet Union
  b. the breakup of Yugoslavia
  c. the fall of the Berlin Wall
  d. the fall of the Great Wall of China