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
Thromboasthenia there is a defect in - 
Select and explain. 
A. Platelet adhesion, B. Platelet aggregation, C. ADP secretion, D. Platelet contraction
B: Platelet aggregation
Answer: B: Platelet aggregation 
Explanation: None