Which Is More Important: Basic or Applied Research

Which is more important: basic or applied research?

A) Basic research, because as Kurt Lewin said, "There is nothing so practical as a good theory."
B) Applied research, because this type of research is involved in solving social problems.
C) Neither are that important compared to experimental research, which can establish causality.
D) Both, because basic research allows for an understanding of psychological processes that can be used in applied research to solve social problems.