Option d. as we know the corner of a square is always 90°. So we can apply that (side of the square)^2+(side of the square)^2 = (diagonal of the side)^2
(side of the square)^2+(side of the square)^2 = 16 16/2=8 8=(side of the square)^2 side of square= squareroot of 8 area of square= squareroot of 8^2=8 hence answer is 8
