From a managerial perspective, which budget is most likely to motivate people to succeed in executing it?

A budget that is tight, but attainable because it creates the appropriate level of challenge.

A budget that is easy to achieve, because it inspires confidence.

A budget that is difficult to achieve, because it encourages people to aim high.

A budget that is tight, and nearly impossible to achieve, because it creates camaraderie and an "us versus them" mentality.