It is generally agreed that the existence of some form of target or expected outcome is a greater motivation than no target at all. Therefore (1) is true. The establishment of a target, however, raises the question of the degree of difficulty or challenge of the target. Therefore (2) is true. If the performance standard is set too high or too low sub-optimal performance could be the result.
The degree of budget difficulty is not easy to establish. It is influenced by the nature of the task, the organisational culture and personality factors. Some people respond positively to a difficult target. Others, if challenged, tend to withdraw their commitment. So (3) is not true.