Answer: Option (c) is correct
Step-by-step explanation:
Code of ethics are the principles that are created by psychologist.These guidelines define about integrity ,confidentiality,honesty,etc. Research participant's information is considered as confidential according to investigator to maintain security and not disclosing it to external factors.
Other options are incorrect because using animals as participants, reducing double blind method or financial incentive use are not the factors that investigators take care of whole researching. Thus, the correct option is option(c).