Find the area of the green sector(s). The diameter is 12.

The answer is B.
The area of a circle is pi x r^2
If the diameter is 12, the radius is 6
3.14 x 36 = 113.04 - that is the area of the whole circle
Then you divide it by two because half of the circle is the green sectors.
113.04/2 = 56.52