What had John done before Mike started working out at 6am?

The correct choice is that John had finished his workout before Mike started working out at 6 a.m. This option indicates that John completed his exercise routine prior to the time when Mike began his workout, establishing a clear chronological sequence. In this context, it suggests that John's morning routine was well underway, likely starting well before 6 a.m., allowing for the completion of his workout.

Understanding this relationship in timing illustrates the concept of events occurring in a specific order; one action (John's workout) happened and was completed ahead of another action (Mike starting his workout). The other options do not effectively convey a completed action in relation to Mike's 6 a.m. start time. For instance, "had breakfast" or "gone to bed" might not necessarily indicate the completion of an activity before Mike's workout time in the same way that "finished his workout" does. Similarly, "started his day" could imply a variety of activities without specifying completion or direct relation to time, making it less precise in indicating John's prior actions.