A researcher records a child's crying behavior when the child is at school and when the child is at home and provides treatment at school then at home. The researcher is using a(n) design.

Multiple baseline design.

Explanation:

Multiple-baseline design explains how it is possible to study and acquire a better knowledge about the effectiveness of the treatment, due to the way it is gradually dispensed over time. The main feature is to show these changes through different baselines, usually two or more behaviors are observed and act as separate baselines, intervention is introduced to one of the behaviors and then to the other. For this, the baselines of various behaviors that can be modified with the same treatment are first recorded. The treatment is applied to one of them (first behavior) and the changes caused in it are observed. Treatment is applied to the second behavior and the changes are observed. It is continued sequentially until the treatment has been applied to all the behaviors under study. In all cases, treatment is applied when behavioral stability has been achieved.