Which sentence does not contain any punctuation errors? A. My brothers cleaned up washed dishes and put the leftovers in the ref
rigerator. B. My brothers cleaned up, washed dishes, and, put the leftovers in the refrigerator. C. My brothers cleaned up, washed dishes and put the leftovers in the refrigerator. D. My brothers cleaned up, washed dishes, and put the leftovers in the refrigerator.
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).
So this question doesn't seem to be complete since there isn't any answers to choose from but my guess that the author thinks the underground railroad was really cool or served many helpful purposes or something like that. It wouldn't be something negative so whichever one fits most into context.
