For a set of points on plane below, there are 7 points which contain 4 extreme points. What's the number of diagonals and triangles after applying triangulation for the points?
如下图所示的一个点集合，其中点数为7，极点数目为4，那么进行三角剖分之后的引入的对角线和三角形的数目分别是？
A15, 7
B14, 9
C15, 8
D14, 8