Answer:
b. No, this does not need to be reported since it is unrelated to participation in the study.
Step-by-step explanation:
The researcher should only report facts that are linked to the research objective and that can in any way influence the research data. The researcher should report these facts, so that some modifications can be made, making it possible for the research result to be as unbiased as possible.
In the case of the research reported in the question, the researcher need not report on the case of the patient who had a heart attack, as the research is on hygiene and disease prevention and the heart attack is irrelevant to the research results.