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).
c. persuade the commissioners to place street lamps along the road
If an essay is order Chronologically, then it is more or less like steps. So we would want a(n) transitional phrase that sounds like it could fit into a step process. That would be "Afterward," This phrase is most likely to show up in a chronological essay than the others. If you look at the others they are all shadowing further elaboration on something.
The answer is afterward
