How Did Lisa Wade Research Hookup Culture for Her Essay

How did Lisa Wade research hookup culture for her essay, "American Hookup: Deep in the Fog"?

A) She had students in several of her sociology classes keep journals that she collected at the end of the term.
B) She analyzed data from a large survey project done over many years by another sociologist.
C) She talked with students wherever she traveled and spoke on college campuses.
D) She used all of the above methods in her research.