Which type of research design is often used to investigate causal relationships?

The correct answer is experimental design because it is specifically structured to identify cause-and-effect relationships between variables. In an experimental design, researchers manipulate one variable while controlling other variables to observe the effect of this manipulation on another variable. This allows for a clear determination of whether changes in one factor directly cause changes in another, which is a fundamental aspect of causal research.

In contrast, correlational design examines the relationships between variables without establishing a cause-and-effect link. It identifies patterns or associations but does not account for external influences. Descriptive design focuses on providing a detailed account of a phenomenon as it is, without manipulating variables, hence it cannot establish causation. Exploratory design aims to explore a research question in a more open-ended manner, usually when the topic is not well-defined; thus, it is not suitable for determining causal relationships.