This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorder of Metabolism & Connective Tissue, Subject name: Medicine
Wilson's disease is diagnosed by? 
Select and explain. 
A. Increased serum ceruloplasmin, B. Decreased liver copper, C. Increased urinary copper excretion, D. Decreased urine copper excretion
C: Increased urinary copper excretion
Answer: C: Increased urinary copper excretion 
Explanation: ANSWER: (C) Increased urinary copper excretionREF: Harrison's Internal Medicine 17th ed> Chapter 354. Wilson Disease >Useful Tests for Wilson DiseaseTestUsefulnessNormal ValueIn Heterozygous CarriersIn Wilson DiseaseSerumceruloplasmin+180-350 mg/LLow in 20%Low in 90%KF rings++AbsentAbsentPresent in 99% + if neurologic or psychiatric symptoms present.Present in 30-50% in hepatic presentation and presymptomatic state24-h urine Cu+++0.3-0.8 mol (20-50) gNormal to 1.3 mol (80 g)>1.6 mol (>100 g) in symptomatic patients 0.9 to >1.6 mol (60 to >100 g) in presymptomatic patientsLiver Cu++++0.3-0.8 mol/g (20-50 g) tissueNormal to 2.0 mol (125 g)>3.1 mol (>200 g) (obstructive liver disease can cause false-positive results)Haplotypeanalysis++++(Siblings only0 Matches1 Match2 Matches