Seven students, A, B, C, D, E, F, and G, have been selected to be possible characters in a school play. Only 4 people will actually be in the play. The narrowing of the field must obey the following rules: D can only be selected if G is selected. E cannot be selected unless B is selected. Either G or A must be selected, but not both. Either E or C must be selected, but not both. Which of the following, if selected for the show, will completely determine the makeup of the four on the show?