Which of the Following Statements About a Two-Way Analysis of Variance

Which of the following statements about a two-way analysis of variance model is/are TRUE?

A) The population of interest is classified according to two categorical variables,or factors.
B) An experiment involving the simultaneous use of two factors offers advantages over two one-way experiments with respect to such matters as efficiency and reduction of residual variation.
C) The two-way type of experiment requires twice as many experimental observations as would be required in two one-way experiments of the same factors.
D) An experiment involving the simultaneous study of two factors allows for the investigation of interactions between the factors.
E) Only A,B,and D are true.