Which election method allows citizens to place proposals on the ballot for voter approval? If the measure passes, it becomes law

During the height of the Cold War, what would the United States likely have done if it had discovered that the Soviet Union was secretly installing nuclear missiles in another country close to the United States?

a. allowed the missiles to be delivered and then sent in military forces to confiscate them b. engaged in a direct military conflict with the Soviet Union c. blocked the transport of the missiles while finding a way to negotiate an agreement with the Soviet Union d. withdrawn from NATO and unilaterally attacked the Soviet Union

What aspect of the A-B-A design helps us determine whether the treatment, as opposed to some other variable, was responsible for any observed changes in behavior?

a. seeing whether the target behavior returns to original levels when treatment is removed b. observation of both a treated and yoked control participant c. starting with the observation of other cases d. returning to observe behavior under treatment several weeks after the experiment is over