Answer:
a. Divide the surface area of the sphere by 2, and add the area of the base of the hemisphere.
Explanation:
The surface area of a sphere is given by:

The surface area of a hemisphere with the same radius is given as :

We can see that the surface area of hemisphere is half the surface area of the sphere.
But as a sphere is a round shape but hemisphere is a hollow one. So, we will add the area of the base of hemisphere to the surface area of the hemisphere.
Therefore, the right answer is A- Divide the surface area of the sphere by 2, and add the area of the base of the hemisphere.