Answer: d. collect as many clues as possible
Step-by-step explanation:
When carrying out an investigation or research, taking a bias or a one sided information would be a partial and incomplete judgement for the researcher to conclude on, the best approach to every research, investigation is to endeavor that all information is gotten about the case, this is possible by gathering as many clies as possible; every information that relates to the answer. When this is done, makes it easier to gather information about a personality and draw out a conclusion.