The area of a triangle ( one of the sides) is 1/2 x base x height
base = 16, height = 19
Area = 1/2 x 16 x 19 = 152 square units.
There are 4 sides: 152 * 4 = 608 square units
The area of the bottom square is 16 x 16 = 256 square units.
Total area = 608 + 256 = 864 square units.
The answer is D.