Answer: Four
Explanation: Since there is a pyramid in the diagram based on a quadrilateral, meaning that it has four sides given as triangles, meaning a total of five faces. The four sides given as triangles have a common point B, which is also the top point of the pyramid, so said point B lies on four faces. We can view four triangles as four planes, and each point in the plane, even if it is an end point on the edge of the plane, belongs to that plane. Point B does not belong to the base of the pyramid, the fifth face that is the quadrilateral.