SAT Boundaries Question

In a 2022 study, Fa-Gang Wang et al. concluded that other artifacts excavated from an archaeological site in China date to between 39,000 and 41,000 years ago. The reliability of the dates that Wang et al. have posited, which were obtained through processes that determined when buried mineral grains surrounding the ocher artifacts were last exposed to sunlight, in part upon the researchers' exclusion of mineral grains that lacked adequate sun exposure before burial. Which choice completes the text so that it conforms to the conventions of Standard English?