Answer:
A. It can be any polygon.
Explanation:
A pyramid is a polyhedron with a base, which can be any polygon, but is most often a square.
When the base is a triangle, the pyramid has a total of four faces.
The famous Egyptian pyramids have square bases and four triangular faces. As the number of sides increases in a pyramid, it begins to look like a cone.
So, we can say A and C are both correct. But we will go with A as a square will also be considered in it.