Which of the following is a cohort-sequential design? a.            The impact of adolescence on the aggression level in boys between the ages of 8 to13 and 13 to 18, for a period of 5 years till they...

Which of the following is a cohort-sequential design?

a.            The impact of adolescence on the aggression level in boys between the ages of 8 to13 and 13 to 18, for a period of 5 years till they reach ages 13 and 18, respectively

b.            The sustenance of sports activity and subsequent career choices of 30 children who were identified to have high potential for sportsmanship, for a period of 5 years during high school and college

c.             The impact of activity-based teaching methods on the learning ability of children in grades 6–10, as compared to pedagogical methods

d.            All the above