All of the below speed up the diffusion process, except
a) If the new product has a definite relative advantage over earlier models, diffusion is quicker.
b) If the product category is very observable, and we can see others use it, diffusion is quicker.
c) If the product is very complex, diffusion is quicker.
d) If it is low-risk to try the product, (such as a new sandwich, not a new cell phone) diffusion is quicker.
e) If it is part of an established product line, and risk is perceived low, diffusion is quicker.