The definition of sloth would be laziness, unwillingness to work or act.
Two context clues are the word "idleness" and the phrase "doing of nothing". Idleness may mean boredom, but also dullness. Doing of nothing clearly supports the notion of not working, not acting.
Harper Lee characterizes Atticus as a hard working attorney who’s pretty straightforward with his children, especially scout.
The answer to your question is reserved words. your welcome.
The correct answer is: Option A. Adopt the horses.
Given the context in the excerpt stating the individuals that would be "taking possession of the new horses" are official U.S. Marines, it can be inferred that this practice will take place within legal bounds, and therefore "stealing the horses" is out of context in this case. The intent of this activity is to use the horses as part of the Marines' activities, and as such, it is clear the Marines are planning to "adopt" the horses, not "borrow" them.