Which one of the following belongs to the category of good 'research ethics'?

• A. Publishing the same paper in two research journals without telling the editors
• B. Trimming outliers from a data set without discussing your reasons in a research paper
• C. Conducting a review of the literature that acknowledges the contributions of other people in the relevant field or relevant prior work
• D. Including a colleague as an author on a research paper in return for a favor even though the colleague did not make a serious contribution to the pape