Answer:
A pair of intersecting straight lines which agrees with option A of the answers in the list
Explanation:
Recall, how a cone is built, as the surface produced by a line (called the "generatrix") as it moves at a fixed angle pivoting around a fixed point that will become the "vertex" of the cone.
As a plane cuts the cone perpendicular to its base and passing through the vertex, it will just intersect the generatrix trajectory in exactly two locations.