Answer:
A. To explain why he came to Birmingham.
Step-by-step explanation:
Option A is the correct choice that states King's purpose for writing this letter.
This option correct because looking at the letter, King opened it by saying. "I think I should give the reason for my being in Birmingham..."
this statement he made at the opening of the letter reveals that the purpose of his writing is to explain why he came to Birmingham.
Martin Luther King, Jr., was known as a Baptist minister. Also, he was popularly known to be a social rights activist and a leader of the American civil rights movement in the United States.