City High School must put together a debating team consisting of four debaters.There are candidates of equal ability : X,Y and Z who are all seniors; and A,B,C and D who are all juniors..The school requires that there should be two seniors and two juniors in the team.It is also necessary that all of the debaters be able to work with one another. *Debaters Y and A cannot work together. *Debaters Z and C cannot work together. *Debaters A and B cannot work together. which of the following statements must be false? 1.Debaters Y and C are never selected together. 2.Debaters Z and D are never selected together. 3.Debaters Z and D are never selected together.