What is the relationship between the number of vertices in each polygon and the number of isosceles triangles?
The image consists of three figures, first is of a regular square with diagonals intersecting each other, second is is of a regular pentagon whose vertices are joined to its centre and third is of a regular hexagon with diagonals intersecting each other.

A.The number of vertices is 1 more than the number of isosceles triangles.
B.The number of vertices is equal to the number of isosceles triangles.
C.The number of vertices is 1 less than the number of isosceles triangles.
D.The number of vertices is 2 less than the number of isosceles triangles.