Official Explanation
The area of the shaded region is the area of the square minus the area of the portion of the circle that is inside the square. The area of a square is its side squared. The area of square ABCD is \(4^2 = 4 × 4\), which is 16. Now find the area of the portion of the circle that is inside the square. Because the diameter of the circle is a side of the square, you know that exactly one-half of the circle’s area is inside the square. Also, because the diameter of the circle is twice the radius, the radius of the circle is \(\frac{4}{2}\) or 2. The area of a circle with a radius r is \(πr^2\). The area of the complete circle in this question is \(π(2)^2\), which is \(4π\). So half the area of this circle is \(2π\). Thus, the area of the shaded region is \(16 - 2π\). That means that \(16 - 4π\) and 16 - 16π are less than \(16 - 2π\), so they cannot be correct choices. However, the sum of 16 and any positive number is greater than 16 and also greater than \(16 - 2π\). So, the correct choices are (C), (D), and (E).