The correct answer is B) Republicans in Congress did not trust white southerners to adopt reforms giving rights to freed slaves.
Congress divided the South into military districts because Republicans in Congress did not trust white southerners to adopt reforms giving rights to freed slaves.
That is why the United States Congress passed the Reconstruction Acts of 1867 and divided the South into five military districts. Let's have in mind that the Civil War had ended and there were still many "wounds" in southern people after the end of slavery. The South depended so much on slavery to produce the crops that had to be traded and exported. The US Congres wanted to make sure that the southern states obey this legislation and respect the rights of the African Americans.