Which principle was established by the nuremberg trials after world war 2

Powers of states the first letter of the answer is r.

Which of the following world and national events led to a new view of people with disabilities in the us:     a.  world war i and ii veterans with disabilities returned home after the wars.b.  john f. kennedy was elected president and had a sister with a disability.c.  the civil rights and feminist movements.d.  all of the above.

In atleast 150 words evaluate the effectiveness of the presidential election process in the united states