Answer:
Some of the options are missing, but the answer is: Workers
Explanation:
Vulnerable persons in this context refers to the people who are not in their full mental or physical condition to operate like normal citizens. So, when these people are used as a subjects in an experiments, they will be granted additional protection to ensure their safety during and after the research.
People who held the status as 'Workers' , are most likely in a good physical and mental condition (otherwise they wouldn't get their job). Because of this, they are not included in 'vulnerable persons' category.
