The parallelogram's perimeter is determined by adding the lengths of its sides. With two pairs of parallel sides, one 18 meters long and the other 6 meters, the total perimeter is 54 meters (Option B).
The perimeter of a parallelogram is the total length of all its sides added together. In the given diagram, we can see that the parallelogram has two pairs of parallel sides: one pair with length 18 meters and the other pair with length 6 meters. Since opposite sides of a parallelogram are equal in length, we know that the perimeter will include two sides of 18 meters and two sides of 6 meters.
Therefore, the perimeter of the parallelogram can be calculated as:
Perimeter = 18 meters + 18 meters + 6 meters + 6 meters
Perimeter = 54 meters
So the answer is B. 54.