A, B, C, D, E, F are to be given adjacent rooms .The rooms don't have complete walls between them rather sound, smoke can easily get through from one to another as there are gaps over a wall for free exchange of air. Miss C the head is allotted room no 5 as wished by her. Miss E needs a telephone for regular communication. Mr A & Mr B prefer to have adjacent rooms. Mr B, C, D are chain smokers. Miss C is allergic to cigarette smoke. The correct order of placement of rooms is?  Which slot is best for Mr A?