Which of the Following Is True Regarding Causal Research

Which of the following is true regarding causal research?

A) Causal research is the questions of who, what, where, when, and how.
B) Causal research isolates what factor(s) cause an event.
C) Causal research is informal and unstructured.
D) Causal research describes marketing phenomena.
E) Causal research is the seventh step in the marketing research process.