Which of the Following Statements Is True When Considering Experimental

Which of the following statements is true when considering experimental versus non- experimental designs?

A) Descriptive research offers little control over other possible causal factors.
B) In descriptive research, it is also difficult to establish time order of occurrence of variables. However, in an experiment, the researcher controls the timing of the measurements and the introduction of the treatment.
C) It is difficult in descriptive studies to establish the prior equivalence of the respondent groups with respect to both the independent and dependent variables. However, experiments can establish this equivalence.
D) All of the above statements are correct.