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.
Mexican-American is her nationality
Doesn't he think that he hears the heart beating under the floor board?
Because he hears this faint beating leaving him to be paranoid that the cops know that he hid that guy under there.