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
Safest treatment of hyperthyroidism in pregnant women is: 
Select and explain. 
A. Radioactive iodine, B. Methimazole, C. Carbimazole, D. Propylthiouracil
D: Propylthiouracil
Answer: D: Propylthiouracil 
Explanation: None