Final answer:
Descriptive research explains what happened, while Correlational research explores why it happened. The correct answer choice is 4) Descriptive research, Correlational research.
Step-by-step explanation:
The goal of Descriptive research is to tell "what" occurred, whereas the goal of Correlational research is to tell "why." Descriptive research aims at depicting the characteristics of a phenomenon or the state of affairs as it is at the moment of the study. On the other hand, correlational research seeks to identify relationships between variables and the degree to which these variables can predict each other.
Experimental research is also linked to understanding the "why" aspect by manipulating one variable to study its effect on another, establishing cause-and-effect relationships. However, the distinction between descriptive and correlational research is more relevant to the presented choices. It is important to note that each research method has its unique strengths and weaknesses and is chosen based on the specific research question at hand.