When you enumerate you need to put comas between all the items except the ones which are connected by "and" : as A is not correct as it does not have comas, and B is incorrect as it has comas where "and" is.
now, in a way both C and D are correct, but C is the usual accepted version, and D is an example of "Oxford coma" (where the coma is optional, to remain on the safe side, choose C).
Answer Literal
Example:
"Techniacally it doesn't actually fly, it's just a metal plane model."
Definitely c because it happens in movies nowadays .... and mostly starts with good beginnings then bad phases through the movie then the actor realizes what he has done .. after a period of time