The correct option is _ C). Conducting regular safety inspections _

A supervisor has many roles to play to ensure the safety of employees under his/her supervision. The supervisor has to perform various formal activities in this regard. But the main and first priority during his/her duty time is to conduct safety inspections regularly. This is important as the supervisor is working in the same environment as the employees day after day and thus is well qualified to make observations and uncover noncompliances when doing regular safety inspections in the workplace. The supervisor then will ensure that the proper corrective actions get implemented. This the most active and important way to ensure that the employees can enjoy a safe environment without hazards or risky activities that could lead to accidents.

Option A). is incorrect. The organization's safety policies may be written by the safety manager if the company has one otherwise the supervisor may do it as well. In any case, even if the supervisor writes the organizational safety policies it is not in their primary role of observing and coordinating the activities performed by the employees in the operation.

Option B). is incorrect. Developing online safety manuals may be done and can help the organization improve its safety performance. However, it is likely not to be done by the supervisor and certainly is not part of the supervisor's primary role.

Option D). is incorrect. This is because attending safety training workshops is also an important measure but not a primary supervisory function.