Having never used Salesforce before, I can only assume that perhaps the previous answer knows the system. However, I can give you my best guess. If a workflow task means what I think it means (basically that this task has to be done at multiple points in multiple processes), then I can immediately tell you that you should be able to reuse the workflow task in multiple rules (answer A) and that it can be tracked in the activity history (answer B).
Answer B is actually the answer that makes the most sense. This activity needs to be tracked, and if you can’t see it in the activity history, something has gone wrong and it needs to be fixed, pronto.