I personally would go with C if compound is the underlined word. Not sure, hope this helps though!
A descriptive research is one that provides data that allows conclusions about something that is happening in reality, that is, this type of research searches about something palpable and identifiable in the physical world in which we live. An example of this type of research is electoral research, since it stipulates the real probability that a candidate for some political office will win an election that is in progress.
A correlational research is one that seeks to assess the relationship between two or more variables, within a reality. In other words, they are surveys that provide cause-and-effect data, promoting the conclusion on a given subject. As an example, we can mention a research that seeks to analyze whether a good economy in a country promotes a higher incidence of cases of depression in a society.
Experimental research is one that seeks to do a kinetic investigation, testing hypotheses through a set of two sets of variables, where one set is kept constant, while the other is measured in order to generate results. An example of this can be seen in laboratory research, for example, a research that seeks to study the formulation of drugs manufactured based on plant extracts that seek to eliminate the spread of coronavirus.
