The best course of action in this scenario is to assess the third party’s safety in addition to assessing the safety of the person the third party is reaching out about. This ensures that both individuals' safety is prioritized and appropriate steps are taken to provide the necessary support. Depending on the assessment, additional actions such as transferring the call, encouraging the individual to reach out to a hotline, or contacting emergency services may also be necessary. Therefore, while assessing safety is essential, it may be necessary to consider elements from the other options as well.
However, none of the other options adequately encapsulate the comprehensive approach needed in this scenario. Therefore, if required to select just one answer, choice "Assess the third party’s safety in addition to assessing the safety of the person the third party is reaching out about" would be the most appropriate single answer.
If "All of the above" were a possible answer, that could also be valid, as it would cover multiple necessary steps in managing the situation effectively. But directly addressing both individuals' safety is a priority.