A nurse in dialysis center is caring for a client who has a new diagnosis of end-stage kidney disease. When he arrives for his first dialysis treatment, he tells the nurse, "I decided to come today, but I am not sure if I will need to come back again this week. I am feeling much better since my discharge from the hospital and I think my kidneys are working again." The nurse should identify that this client is demonstrating which of the of the following Kübler-Ross stages of grieving?