The U. S. Senate is composed of 2 senators from each of the 50 states. For a treaty to be ratified, at least two-thirds of the senators present must approve the treaty. Suppose all senators are present and 48 of them have voted in favor of a treaty. What are the possible numbers of additional senators who must vote in favor of the treaty to ratify it? A. at least 12 senators B. at least 18 senators C. at least 19 senators D. at least 20 senators