This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Drugs used for rare diseases are known as 
Select and explain. 
A. Orphan drugs, B. Rare drugs, C. Radioactive isotopes, D. Alkylating agents
A: Orphan drugs
Answer: A: Orphan drugs 
Explanation: An orphan drug is a pharmaceutical agent developed to treat medical conditions which, because they are so rare, would not be profitable to produce without government assistance. The conditions are referred to asorphan diseases Refer 6/e p6