What exception cannot be used by teams that are above the Apron?

The Bi-Annual Exception is unique because it is specifically designed for teams that are below a certain salary threshold, known as the Apron. When a team exceeds the Apron, they are restricted from utilizing this exception, which limits their ability to sign players more flexibly.

On the other hand, the Mid-Level Exception, Veteran Minimum Exception, and Rookie Exception have different stipulations in their usage. The Mid-Level Exception can be used by teams under the salary cap and can be prorated for teams above the apron; the Veteran Minimum Exception allows teams to sign veterans for a minimum salary regardless of their cap situation; and the Rookie Exception does not have limitations related to the apron. Thus, the answer reflects an understanding of salary cap rules and transaction mechanics that govern NBA teams.