: 20Constraints control events or activities that __________________.

 Role of Constraints:

Constraints impose specific conditions on schedule events or activities, such as fixed start dates or imposed milestones.

These are external to the natural logic relationships established in a network (e.g., predecessor-successor relationships).

 PSP Study Guide References:

The guide describes constraints as independent factors that override logic-based sequencing when necessary​.

 Analysis of Options:

Option A and C: Constraints impact both forward and backward passes, not exclusively one.

Option D: Constraints supersede activity logic rather than being overruled by it.

 Conclusion: The correct answer is B, as constraints operate independently of project logic relationships.