单选题 The nurse is assisting with a subclavian vein central line insertion when the client's oxygen saturation rapidly drops. He complains of shortness of breath and becomes tachypneic. The nurse suspects a pneumothorax has developed. Further assessment findings supporting the presence of a pneumothorax include
A. diminished or absent breath sounds on the affected side.
B. paradoxical chest wall movement with respirations.
C. tracheal deviation to the unaffected side.
D. muffled or distant heart sounds.