The given figure is compounded by a semicircle and a triangle as can be seen in the following diagram:
The area of a semicircle is given by the formula:

Where r is the radius of the semicircle, which is the half of the given diameter, then r=16/2=8 m. By replacing this value we can find the area of the first part:

Now, the area of the triangle is given by the formula:

Where b is the base and h is the height. The base is b=16 m and h=12 m. Replace these values and find the area of this part:

Finally, the total area of the figure is the addition of the two areas we found:

The answer is B. 196.5 m^2