A 60-Year-Old Male Patient Has Been Treated for Pneumonia for the Past

A 60-year-old male patient has been treated for pneumonia for the past 6 weeks.He is in the clinic to check an "unexplained" weight loss of 4.5 kg (2 lb) over the last 6 weeks.The nurse knows that:

A) his weight loss is probably from unhealthy eating habits.
B) chronic diseases such as hypertension don't cause weight loss.
C) unexplained weight loss often accompanies short-term illnesses.
D) his weight loss is probably not the result of a mental dysfunction.