Which of the following best describes a sequential design?

A sequential design permits researchers to check if cohort effects are operating. This design involves combining cross-sectional and longitudinal research, allowing for the comparison of different cohorts at different ages. By using this approach, researchers can determine if developmental changes observed are due to age or generation-specific factors. Therefore, a sequential design is valuable in addressing the potential influence of cohort effects on developmental outcomes. Choices A, C, and D are incorrect because a sequential design does not neglect diversity in developmental outcomes, is not necessarily less efficient than a longitudinal design, and can make both cross-sectional and longitudinal comparisons.