Answer D, 72
The diagonals of a square bisect one another at right angles forming 4 isosceles right triangles with leg lengths 6 units. (The vertices (2,10) and (2,-2) are vertical and the other two are horizontal. The diagonal has length 10-(-2)=12 so both diagonals are bisected making the length of the legs of all 4 triangles 12/2=6 units.) if we put two of the triangles together we get a square of side 6, area 36. Since there are 2 pairs making up the area of the square, the latter is 2×36=72 square units.