三幕戏剧的第二幕占整个戏剧长度的$$\frac{1}{3}$$，如果第一幕是第三幕的两倍，那么第三幕占整个戏剧的几分之几？  The $$2$$nd act of a $$3$$-act play is $$\frac{1}{3}$$ the length of the entire play. If the $$1$$ st act is twice as long as the $$3$$rd, what fraction of the play is the $$3$$rd act? 
选项为:A:$$\frac{1}{9}$$  B:$$\frac{2}{9}$$  C:$$\frac{3}{9}$$  D:$$\frac{4}{9}$$  请回答其中一个选项.