Regarding "Diffusion" based AI art generators, which of the following is FALSE?

a$.$ They require a great number of images to create the "model."

b$.$ At some point in the process, noise is $*$added$*$ to an image.

c$.$ At some point in the process, noise is $*$removed$*$ from an image.

d$.$ New images typically begin as a uniform blank white square.