What is the purpose of King’s "Letter from a Birmingham Jail”?

A. to show that Birmingham leaders need to find new ways to negotiate with African American leaders instead of jailing them for marching without a permit
B. to demonstrate that the Birmingham clergymen who criticize King want to stop African Americans from gaining equality in their city
C. to explain that the protests led by King in Birmingham are necessary because the local leaders and courts are not willing to confront the issue of segregation
D. to illustrate that the violence associated with King’s protests in Alabama is justified because a person who attacks a protestor should also be attacked