Let O be the intersection of the vertical line through ZX, and the horizontal line through YW.
The coordinates of this point are clearly (5, 2) as it is at the same x-coordinate as X and Z, and y-coordinate as Y and W.
So, YZO is a right triangle. By the Pythagorean theorem:

.
Since all sides of a rhombus are equal, then the perimeter is :

units.
Answer: third choice.