Which of the following is a key difference between social evolutionism and diffusionism?

Which of the following is a key difference between social evolutionism and diffusionism?

a.evolutionism suggested that "primitive society" was better off than its "civilized" counterpart (e.g. the idea of the noble savage)

b.diffusionism sought to explore how cultural traits spread from one place to another, evolutionism did not

c.each were concerned with trying to understand "other" (or exotic) cultures

d.each are now recognized as fundamentally accurate approaches