Answer:
D. Informed Consent to Research
Step-by-step explanation:
informed consent to research is a voluntary agreement to participate in a study. the subject must be made aware of the research in details and must consent to it before the start of the research.
in this case, Professor Hammond did not notify the students or seek their consent before the start of the study. However, due to the nature of the study, if the students are aware it may affect the results. thus it is adviceable to notify their guardians for consent.