UCAT Medentry DM Question

Does anybody understand why Celeste can't be chosen? If Fabian is selected and Andy and Bronwyn have to both be selected then how can anyone else be accepted because that's 3 people? So surely that means both Celeste and Dean cannot be chosen?

You can have F + A + C, A +C from rule 2

Thank you for responding and helping , but if A is chosen doesn't B have to be chosen as well from rule 1?