What are the vertex and x-intercepts of the graph of the function below?
y= x2 - 4x- 21
O A. Vertex: (2,-25); Intercepts: x = 3, -7
B. Vertex: (2, 17); Intercepts: x= -3,7
C. Vertex: (2,-25); Intercepts: x= -3,7
O D. Vertex: (2, 17); Intercepts: x = 3, -7