ANSWER
15 square units.
EXPLANATION
Each box is 1 square units.
When we count the number of boxes we obtain 15 boxes.
This implies that the area of the rectangle is 15 square units.
Alternatively, we can observe that:
The rectangle is a 3 by 5 rectangle.
So the area is
[tex]3 \times 5 = 15 \: units \: square[/tex]
The rectangle is 15 units square.
