Jamie plays an adventure video game in which a magic sword appears sometimes to help him score more points. The appearance of the sword is not dependent on Jamie's performance in the game. He does not know when the sword will appear, so he is always prepared to grab it. In the context of operant conditioning, the appearance of the magic sword illustrates a of reinforcement.

Which of the following statements best describes the terms of the treaty of guadalupe-hidalgo? a the treaty ended the mexican-american war, resulting in the u.s. finally being able to finish building railroads in texas. b the treaty ended the mexican-american war, resulting in mexico and the u.s. going back to their pre-war conditions. c the treaty ended the mexican-american war, resulting in the u.s. facing a lot of international backlash for the war. d this treaty ended the mexican-american war, resulting in mexico ceding a large amount of land to the united states.