The type of research that tests hypotheses and theories in order to explain how and why a phenomenon operates as it does is

Explanatory research tests hypotheses and theories to explain how and why a phenomenon operates.

Descriptive research documents what a phenomenon is like without probing its underlying causes.

Predictive research forecasts future outcomes rather than explaining the mechanism behind them.

The none choice is wrong because explanatory research precisely fits this how-and-why purpose.

Explanatory studies typically build on prior descriptive and exploratory findings.

Their goal is to identify causal mechanisms and to test theoretical relationships.