The answer is the option B, which is: B. Similar hexagons.
The explanation for this answer is shown below:
By definition, a cross section is the shape that is formed when a plane cuts or makes a slice through a solid.
The hexagonal pyramid has an hexagonal as its base. If you make slices parallel to the base of this pyramid, you will see the shape of this base in different sizes. Therefore the shapes that are formed by cross sections parallel to the base of the hexagonal pyramid are similar hexagons.