To calculate the volume of the pyramid, we can use the formula:
\[ \text{Volume} = \frac{1}{3} B H \]
where:
- \( B \) is the area of the base of the pyramid.
- \( H \) is the height of the pyramid.
Given:
- The base is square with a side length of 18 meters.
- The height \( H \) is 40 meters.
First, we calculate the area of the base \( B \):
\[ B = \text{side length}^2 = 18 , \text{m} \times 18 , \text{m} = 324 , \text{m}^2 \]
Now, we can substitute \( B \) and \( H \) into the volume formula:
\[ \text{Volume} = \frac{1}{3} \times 324 , \text{m}^2 \times 40 , \text{m} \]
Calculating the volume:
\[ \text{Volume} = \frac{1}{3} \times 324 \times 40 \] \[ = \frac{1}{3} \times 12960 \] \[ = 4320 , \text{m}^3 \]
Thus, the volume of the pyramid is:
\[ \boxed{4320 , \text{m}^3} \]
So the correct option is D. 4,320 m³.