I believe the answer is b. Continued friendship with other countries
A group used in a study or in an experiment, which does not get treatment by the scientists and is used as a foundation to determine the functions of the other tested subjects is known as the control group. The control group is only found in an experimental investigation.
Answer:
Interrupted time series
Explanation:
According to Wikipedia, Interrupted time series analysis, sometimes known as quasi-experimental time series analysis, is an approach for the analysis of a single time series of data known or conjectured to be affected by interventions (controlled external influences).It refer to the specific point at which the intervention was implemented and allow researchers to examine the effect of an intervention where multiple observations are obtained prior to the intervention to establish a baseline.
