This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Which of the following statement best describes an Orphan drug 
Select and explain. 
A. It is a drug which acts on orphan receptors, B. It is a very cheap drug, C. It is a drug which has no therapeutic use, D. It is a drug declared for treatment of prevention of a rare disease
D: It is a drug declared for treatment of prevention of a rare disease
Answer: D: It is a drug declared for treatment of prevention of a rare disease 
Explanation: Ref-KDT 6/e p6 Orphan drugs are used for rare diseases. Eg.erythroprotein for the treatment of anemia in patient with chronic renal failure