Answer:
C. extraneous factors.
Explanation:
Factors other than the survey by itself can influence responses. For example, the gender or ethnicity of the interviewer may influence participants. These factors are known as: extraneous factors. They are unwanted factors in research which could negatively influence/confound the data of a study if not accounted for. All other factors that could contribute to the study data/result other than the factors in consideration are extraneous factors.
