Explanation:

- Option 1: British Diffusionism

- This school of thought focuses on the idea that cultural traits and human activities spread from a few advanced cultural centers to other people and areas.

- G.E. Smith, W.J. Perry, and W.H.R. Rivers are indeed the main proponents of this theory.

- They believed ancient Egypt was a major source of cultural diffusion.

- Option 2: American Diffusionism

- This approach is primarily associated with the cultural transmission and historical connections in North America.

- Franz Boas is a notable figure in this school, not Smith, Perry, or Rivers.

- Option 3: German Diffusionism

- This focuses on cultural circles and the idea of cultures forming from overlapping cultural traits.

- Kulturkreis is a concept commonly associated with this school.

- Option 4: None of the Above

- This option stands if none of the given matches the description.

Option 1: British Diffusionism is the correct answer.