Answer:
5 square units
Step-by-step explanation:
The parallelogram lies entirely in the plane z=2, so we can treat this as a 2-dimensional problem.
In the order given, the vertices do not define a parallelogram. Two of the sides are parallel, but the other two sides cross each other, for a net area of zero.
If we swap the order of the last two vertices, we get a parallelogram that has a base of 1 unit and a height of 5 units. Its area is ...
A = bh = 1·5 = 5 . . . square units