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.
I would say:
The past passed very quickly.
I would have to go with D.Old age slows even the most productive and hard-working people.
Facebook is awful considering it does not protect your privacy, time-wasting, and it can lead to a sense of false consensus.
