Answer:
B. A pair of intersecting lines
Step-by-step explanation:
The attached image can give you an idea of what you get when a plane perpendicular to the base of a cone intersects the vertex of the cone.
__
In the problem statement here, we assume a double-napped cone with no defined base. That means the lines of intersection with the sides of the cone will meet at the vertex point and extend indefinitely in either direction.
The intersection is a pair of intersecting lines.
