Answer:

Step-by-step explanation:
The volume of a prism is given by:

where
is the area of the base, and
is the height of thr prism.
We know that the height is:
u
and the bases of this prism are hexagons.
Thus the area of the base is the area of a regular hexagon:

where
is the number of sides: for an hexagon: 
is the length of each side:
u,
and
is the apothem: 
we substitute all of this to find the area of the base:

and finally we use the formula for the volume:

we get the following:

which is the third option