A. 16 square inches
The area of the composite shape is 40 square inches. Since the top right of the shape is 3in and the right side is 4in, the height of the composite shape is 3in and the width is 4in. Therefore, the area of the entire composite shape is 3in x 4in = 12 square inches.
Since the top right of the shape is 3in and the bottom left is 3in, the height of the rectangle within the composite shape is 3in. As the width of the composite shape is 4in, the width of the rectangle must be 4in - 3in = 1in. Therefore, the area of the rectangle within the composite shape is 3in x 1in = 3 square inches.
Thus, the area of the rectangle within the composite shape is 3 square inches + 3 square inches = 16 square inches.