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
Which of the following is NOT a predisposing for thrombosis and embolism? 
Select and explain. 
A. Atrial fibrillation, B. Prolonged immobilization, C. Huntington disease, D. Prosthetic cardiac valve
C: Huntington disease
Answer: C: Huntington disease 
Explanation: None