What is not true about formulating a research question?

a. Establish a clear relation between the research questions and the problem or topic.

b. Let the set of research questions or sub problems be preceded by one question expressing the main problem of the research.

c. Ask research questions that are answerable by yes or no and do not use the "how" questions in quantitative research.

d. State your research questions in such a way that they include all the dependent and independent variables referred to by the theories, principles, or concepts underlying your research work.​