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
The main clinicalfeature of primary antiphospholipid syndrome is 
Select and explain. 
A. Thrombosis, B. Vascular injury, C. Trauma, D. Bleeding disorder
A: Thrombosis
Answer: A: Thrombosis 
Explanation: None