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: Surgery
Ca prostate commonly metastasises to the veebrae ? 
Select and explain. 
A. Because valveless communication exist with Batson's periprostatic plexus, B. Via drainage to Sacral lymph node, C. Of direct Spread, D. None of above
A: Because valveless communication exist with Batson's periprostatic plexus
Answer: A: Because valveless communication exist with Batson's periprostatic plexus 
Explanation: Ans. is 'a' i.e., Because valveless communication exist with Batson's periprostatic plexus