Which choice most logically completes the text? | Verbal SAT Question

Some geologists have proposed designating the period from 1950 to the present as a new geological epoch (the Anthropocene) characterized by human impact on Earth, but they have struggled to identify reliable stratigraphic markers of the epoch’s onset. Inta Dimante-Deimantovica and a research team investigated whether the initial appearance of primary microplastics—invented and mass-produced for industrial and other purposes, beginning around the middle of the twentieth century—in sediment cores could serve this role. The researchers analyzed Europe’s lake sediment profiles from the late eighteenth century to the present. Microplastics were present in all layers, likely because certain microplastic shapes enabled rapid downward migration. The researchers therefore concluded that __________

Which choice most logically completes the text?

microplastics are not prevalent enough in sediment to serve as a reliable sign of the human impact characteristic of the Anthropocene.

using the earliest presence of microplastics as a stratigraphic marker of the beginning of the Anthropocene is likely to be viable in some locations but is not viable in Europe.

the lowest sedimentary layer in which microplastics are found cannot be treated as indicative of the chronological beginning of the Anthropocene.

the presence of microplastics in sediment dating to the late eighteenth century indicates that the Anthropocene began earlier than has been proposed.