This solid object contains 8 sides.
The side that is facing you has a surface area:
The side exactly opposite this one has the same surface area - 2 sides with this surface area in total.
The bottom side has a surface area:

The side to your right has a surface area:

The side to your left has a surface area:

The side to your top left has a surface area:

The side beside the side to the top left has a surface area:

The side at the very top has a surface area:

Combined, the surface area is:

Therefore the answer is: C