Choose which of the following will be sufficient to find: What time did the bus leave today?
$\text{Statements:}$
- The bus normally leaves on time.
- The scheduled departure is at $12:30$
- $I$ alone is sufficient while $II$ alone is not sufficient
- $II$ alone is sufficient while $I$ alone is not sufficient
- Either $I$ or $II$ is sufficient
- Neither $I$ nor $II$ is sufficient