John Is Nine-Months Old,has Begun Crawling and Will Soon Begin

Multiple Choice

John is nine-months old,has begun crawling and will soon begin walking.He has yet to take steps unassisted.John is a part of a study that is examining in-depth the changes that occur in the development of walking,so he will be observed for the next few months until he has mastered walking.What type of research design is this?

A) longitudinal design
B) cross-sectional design
C) sequential design
D) microgenetic design