Which statement best describes processing in a multilayer perceptron?

a$.$

It only includes parallel processing, because a multilayer perceptron is a prototypical PDP system

b$.$

It includes both parallel and serial processing, because information moves in parallel across layers, but each unit operates in serial

c$.$

It includes both parallel and serial processing, because information moves in serial from one layer to the next, but each layer operates in parallel

d$.$

It only includes serial processing, because a multilayer perceptron can be simulated on a serial machine: the digital computer