Final answer:
The incorrect postoperative intervention for a keratoplasty patient is Encouraging the client to cough and deep breathe.
Step-by-step explanation:
Option D) Encouraging the client to cough and deep breathe is an incorrect intervention in the context of keratoplasty. Coughing and deep breathing exercises are typically recommended after procedures involving the chest or respiratory system to prevent complications such as pneumonia. In the case of keratoplasty, these exercises are not directly related to the procedure or the eye, and therefore, they are not necessary in this context. The nurse should discuss this incorrect intervention with the nursing student and provide guidance on appropriate care for the client undergoing keratoplasty.