Understanding the Value of Good Questioning, Which of the Following

Multiple Choice

Understanding the value of good questioning, which of the following might be considered the most effective question?

A) When did the United States invade Iraq?
B) Why did the United States invade Iraq in March, 2003?
C) What lessons did we learn from the Iraq War?
D) Do you feel the Iraq War has had any effect on Arab-U.S. relations today? Why or why not and what are the most important effects?