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: Medicine
A 26-year-old woman at 38-weeks of gestation comes to the hospital in labour She has been having an uncomplicated pregnancy so far. All her prenatal testing showed no abnormalities In utero, the fetus has a specialised type of circulation of blood from the mother to the fetus. 
While in utero, which of the following structures shunts blood from the pulmonary artery to the descending aorta? 
Select and explain. 
A. Ductus arteriosus, B. Ductus venosum, C. Foramen ovale, D. Ligamentum arteriosum
A: Ductus arteriosus
Answer: A: Ductus arteriosus 
Explanation: None