Answer:
c. selection bias.
Step-by-step explanation:
Selection bias: In psychological research, the term "selection bias" is also referred as selection effect and is described as a bias that is being implemented via a selection of specific data, individuals, or groups for the purpose of analysis in a way in which "proper randomization" is not being achieved, and ensures that the sample is selected or obtained is not "representative" of the specific population that is intended to be "analyzed".
In the question above, the given problem in the researcher's survey is best described as selection bias.