This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Which of the following is true of Wilson's disease 
Select and explain. 
A. increased urinary excretion of copper, B. increased ceruloplasmin in blood, C. decreased copper and ceruloplasmin in serum, D. decreased urinary excretion of ceruloplasmin
C: decreased copper and ceruloplasmin in serum
Answer: C: decreased copper and ceruloplasmin in serum 
Explanation: None