The city of Pompeii, which was buried in ash following the eruption of Mount Vesuvius in

Choice C is the best answer. The convention being tested is the punctuation of a restrictive coordinated noun phrase. No punctuation is needed within or around the coordinated noun phrase “researchers Roberto Scandone and Christopher Kilburn” because it would create an illogical separation between the noun “researchers” and the coordinated noun phrase “Roberto Scandone and Christopher Kilburn.”

Choice A is incorrect because no punctuation is needed. Placing a pair of commas around the coordinated noun phrase “Roberto Scandone and Christopher Kilburn” creates an illogical separation between the noun “researchers” and the aforementioned coordinated noun phrase. In this case, it illogically suggests that researchers in general bear the specific names Roberto Scandone and Christopher Kilburn. Choice B is incorrect because no punctuation is needed between the noun “researchers” and the coordinated noun phrase “Roberto Scandone and Christopher Kilburn.” Choice D is incorrect because no punctuation is needed within the coordinated noun phrase “Roberto Scandone and Christopher Kilburn.”