A researcher watches children on a playground to obtain measurements of their level of activity. Then the researcher watches the children's caregivers on the playground to obtain measurements of their level of verbal reprimanding of children. The researcher hopes to demonstrate that the caregivers' verbal reprimanding is related to children's activity level. This researcher is using the __________.A)​ descriptive research strategy
B) ​correlational research strategy
C) experimental research strategy
D)​ scientific research strategy