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: Dental
Mercury is toxic because it 
Select and explain. 
A. Complexes with hemoglobin to form methemoglobin, B. Inhibits hemoglobin synthesis, producing anemia, C. Inhibits anaerobic glycolysis, D. Binds to sulfhydryl groups
D: Binds to sulfhydryl groups
Answer: D: Binds to sulfhydryl groups 
Explanation: None