Answer:
A. Report this as a Serious Adverse Event (SAE).
Step-by-step explanation:
When undergoing a trial using a medical product, subjects might sometimes experience certain negative effects referred to as Serious Adverse Events. These effects might range from, hospitalization, death, congenital defects, disabilities, etc.
If the medical personnel suspects that the negative effect was as a result of the medical product used, it becomes necessary to report such as a Serious Adverse Event. So, in the scenario above where a participant suddenly misses participation and his death becomes known through public records, suspicions might be that the death was a serious adverse event caused by the study.