This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
[{'content': 'Two variables are highly correlated when "r" is? \nSelect and explain. \nA. 0, B. 0.5, C. 1, D. -1', 'role': 'user'}, {'content': "Answer: C \nExplanation: ANSWER: (C) +1.0REF: Park s 20th ed p. 755Co-efficent of correlation:Denoted by the symbol rDetermines if there is significant association between two variablesValue : between -1.0 to + 1.0It doesn't not show' causationIf value is towards[?] + 1.0 = positive correlation[?] -1.0 = negative correlation [?] 0 = no correlation", 'role': 'assistant'}]