Reread this passage from Narrative of the Life of Frederick Douglass, An American Slave. He said, "If you give a slave an inch, he will take a mile. A slave should know nothing but to obey his master--to do as he is told to do. Learning would spoil the best slave in the world.
What is the connotative meaning of spoil, as it is used in this passage?

A. increase the positive qualities in something rarely used
B. turn something really good into something totally worthless
C. cause someone to expect more than he or she has earned
D. slightly reduce the usefulness of something used often