What is the perimeter of the square below?

A square is shown with one side marked as 5 units.

A.5 units

B.10 units

C.15 units

D.20 units

Since all sides of a square are equal in length, and one side is given as 5 units, then the perimeter of the square would be:

4 x 5 units = 20 units

Therefore, the answer is (D) 20 units.