This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pediatrics, environment and nutrition, Subject name: Pathology
Which of the following trace element deficiency leads to abnormal collagen cross-linking? 
Select and explain. 
A. Zinc, B. Flouride, C. Selenium, D. Copper
D: Copper
Answer: D: Copper 
Explanation: ElementFunctionBasis of DeficiencyClinical FeaturesCopperComponent of cytochrome c oxidase, dopamineb-hydroxylase, tyrosinase, lysyl oxidase, andunknown enzymes involved in cross-linking collagenInadequate supplementation inaificial dietInterference with absorptionMuscle weaknessNeurologic defectsAbnormal collagen cross-linkingRef: Robbins and Cotran Pathologic Basis of Disease; 9th edition; Chapter 9; Environmental and Nutritional Diseases; Page no: 442; Table 9-10