an experimental condition applied to research subjects. a group of subjects who are exposed to a particular treatment. an observed and measured component determined at the beginning of an experiment. a group of subjects who are not exposed to a particular treatment. a measurable entity whose response is created by the process being observed.

Option A, a group of subjects who are exposed to a particular treatment

Explanation:

Research subjects are those who participate in an experiment or in other words research is conducted on them. Subject can be anyone who is being experimented with in a research study.

Hence, all the experimental conditions will be applicable to the group of subjects who are exposed to any particular treatment as a part of research study.

Thus, option A is correct

Social support tends to decrease the effects of stress.
Social support is the feeling that someone cares for us, that in case of need there will be a helping hand and the general feeling that we are part of a supportive social network. There are four types of social support: emotional, instrumental, informational and appraisal.
It is believed that all the different aspects of social support can have a beneficial effect on stress. Through social support, people can communicate their fears and problems, receive another point of view on them and possibly find some solutions.