The correct option is B The study was carried out between 1980 and 1998.
Option (A) is false as the ratio of male participants to women participants in the study was less than 1 : 2 (41934: 84276). The conclusion drawn in option (C) is beyond the scope of the information provided in the passage, which talks about the prevalence of the disease only in the participants, and not about men and women at large. Option (B) is correct because the women were tracked from 1980 to 1998, while men were tracked from 1986 to 1998. Therefore the entire study was carried out between 1980 and 1998. Hence, option (B) is the best option.