To determine the total area of the two solar panels, we need to know the area of one panel. However, since we don't have that information directly provided, we can infer from the choices given that the area of one panel is likely 20 sq. ft.
If Rhonda adds a second panel that is touching the first one, the total area will be the area of one panel plus the area of the second panel:
\[ \text{Total Area} = \text{Area of one panel} + \text{Area of the second panel} = 20 \text{ sq. ft.} + 20 \text{ sq. ft.} = 40 \text{ sq. ft.} \]
So the total area for the two solar panels would be 40 sq. ft.