Answer:
Exploratory Research Strategy
Explanation:
Exploratory research is the form of research which is carried out in those scenarios wherein the problem is not clearly defined.
Such a research is concerned with obtaining clarity on the problem and not exactly aimed at finding out the solution to the problem. It helps in obtaining better understanding of the problem.
Such a research does not provide conclusive solution of the problem as such a research is driven by the motive of exploration i.e findings or inquiring about the problem and studying it's nature.
In the given case, Buckstar aims to determine the reason behind sales decline. Herein, the problem is not clearly specified. This means no parameters have been defined based upon which sales is dependent. This requires Exploratory Research Strategy.