Answer: A."Atelectasis is when part or all of a lung collapses. All of these clients are at risk for atelectasis due to their pulmonary issues listed. A client who is weak and cannot produce an effective cough is at greatest risk because they are not expelling the mucus which can block an airway and cause the collapse. The elderly client is producing an effective cough, the toddler on the ventilator is able to be in-line suctioned to remove secretions. The client with the broken rib who does not want to cough, needs some client education in order to encourage coughing."