This is version b,
There is little difference between version A and version B (quoted from: interviewee: yujianjiang 1 1). Only the teaching methods in solid geometry are different. One is traditional teaching method, and the other is modern vector teaching method. Although the textbooks are different, most teachers can speak them. It's just a matter of how much. Seeing that the teacher is more inclined to that side. I prefer the solution of vectors.