What Is One Difference Between Correlational and Experimental Research

What is one difference between correlational and experimental research?

A) Correlational research rarely involves observational methods.
B) In an experiment, the researcher systematically manipulates one variable and measures the impact on another.
C) Correlational research allows the researcher to draw conclusions about cause-effect relationships.
D) Statistics are used to indicate correlations but are not used to measure differences found among experimental conditions.