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
Essential for tumor metastasis is: 
Select and explain. 
A. Angiogenesis, B. Tumorogenesis, C. Apoptosis, D. Inhibition of Tyrosine kinase activity
A: Angiogenesis
Answer: A: Angiogenesis 
Explanation: Angiogenesis