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: Pharmacology
The aim of post-marketing studies is: 
Select and explain. 
A. Efficacy of the drug, B. Dosage of the drug, C. Deals with alteration of the drug includes absortion, distribution, binding/storage, D. Safety and comparisons with other medicines
D: Safety and comparisons with other medicines
Answer: D: Safety and comparisons with other medicines 
Explanation: None