Henry Smith Is 88 Years Old and Has Been Having

Henry Smith is 88 years old and has been having periods of disorientation and confusion that worsen at night. He has been given a diagnosis of Alzheimer's disease. When you pick up Henry's tray after supper, you observe that he has not touched any of the food. As his nurse, you understand that the most likely cause of his not eating is:

A) He is too depressed to eat.
B) He sees ants in his food.
C) He is too forgetful to remember to eat.
D) He is deliberately obstinate.