The question is incomplete, it lacks options.
A. cross-sectional study B. interrupted time series design C. control series design D. longitudinal study
Answer:
Longitudinal study
Step-by-step explanation:
Longitudinal study can be defined as a type of research method which involves studying a data over and over again for a long period of time. It is possible for longitudinal study to last for years.
Advantages of longitudinal study include:
1) Longitudinal study tends to be very flexible.
2) Longitudinal study provides an in-depth analysis into the subject being researched.
3) It allows the researcher to study the data for a long period of time son as to notice the different changes that occur.
4) Longitudinal study can be used to identify different developmental trends.