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: Dental
How much iodine is required in pregnancy? 
Select and explain. 
A. 150 mg/day, B. 250 mg/day, C. 350 mg/day, D. 450 mg/day
B: 250 mg/day
Answer: B: 250 mg/day 
Explanation: None