Which of the following is considered minimal risk associated with a research study?

Minimal risk in the context of research studies refers to the likelihood and magnitude of harm or discomfort anticipated in the participants, which is no greater than that ordinarily encountered in daily life or during routine physical or psychological examinations.

The correct choice highlights a type of study that presents only minor changes to previously approved research. These minor modifications are generally unlikely to introduce significant risk, as they are typically limited to what has been vetted and approved before, maintaining the principle of minimal risk. This is crucial in research ethics, as it allows for the continuation and expansion of research without compromising participant safety.

In contrast, studies that involve medication trials or invasive procedures inherently carry higher risk, as they introduce elements that can lead to physical harm or adverse effects beyond what participants would typically experience in daily life. Additionally, research involving the general population without controls can lead to unpredictable outcomes and ethical concerns, further elevating the potential risk involved. Each of these types of studies tends to involve more substantial risks than studies that only incorporate minor changes to previously approved research protocols.