Answer:
D. longitudinal design
Explanation:
Longitudinal design: In research, the longitudinal design is referred to as the study of a group of variables or a variable carrying the similar cases, subjects, or participants over a particular period (week, month, or year). A longitudinal study or design is also denoted as a panel study or longitudinal survey. It includes the process of repeated observation consisting of a similar variable over time.
In reference to the question, the given scenario represents the longitudinal design.
