4. How did Colonel Lloyd attempt to catch slaves who stole from his garden? A. He posted a twenty-four hour guard. B. He employed other slaves as spies. C. He put a barbed wire fence around it. D. He tarred the fence so anyone who touched it would be found out.

This question is about a specific event in the narrative "Narrative of the Life of Frederick Douglass, an American Slave" by Frederick Douglass. In this narrative, Colonel Lloyd, a slave owner, uses a unique method to deter slaves from stealing from his garden. The correct answer is found in the text where Douglass describes Colonel Lloyd's method of catching slaves who stole from his garden. The method involved a tarred fence, which would mark anyone who touched it, thereby exposing their theft. This method is not about posting guards, employing other slaves as spies, or using a barbed wire fence, but rather a clever use of tar on the fence to catch the perpetrators.