The answer is NOT D. A treaty between the U.S. and the U.S.S.R. to end nuclear tests in the atmosphere. I just took the test and got that wrong. The correct answer has got to be either A or C, but I'm leaning more towards C. Just because there are answers that are Verified does not mean they are correct. This is the second time I've used the answer from a Verified response incorrect, so don't trust every verified answer given. Try doing your own research so that you don't mess up the way I did, and then from there compare what you've learned to the options and other people's answers.