Which of the Following Patients Is at GREATEST Risk for Delirium

Which of the following patients is at GREATEST risk for delirium?

A) A 43 year-old male,48 hour status post-rotator cuff repair who is taking analgesic medication for pain
B) A 72 year-old female,3 days post-cataract surgery being seen in outpatient physical therapy for balance retraining
C) A 37 year-old male 24 hours post-coronary artery bypass surgery recovering in the cardiac intensive care unit
D) A 66 year-old female,type I diabetes with a 4 year history of renal failure and dialysis,24 hours after kidney transplant