The points in the graph below represent the halts of a lift for durations of $1$ minute, over a period of $1$ hour.
Which of the following statements are correct?
- The elevator never moves directly from any non-ground floor to another non-ground floor over the one hour period
- The elevator stays on the fourth floor for the longest duration over the one hour period
- Only i
- Only ii
- Both i and ii
- Neither i nor ii