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: Pathology
Which one of the following disorders is due to maternal disomy of chromosome 15? 
Select and explain. 
A. Prader -Willi syndrome, B. Angelman syndrome, C. Hydatidiform mole, D. Klinefelter's syndrome
A: Prader -Willi syndrome
Answer: A: Prader -Willi syndrome 
Explanation: . Prader -Willi syndrome