You are developing a detailed critical path schedule for a proposed petrochemical plant.

 Key to Duration Accuracy:

A specialized industry handbook offers standardized and validated task durations tailored to the specific context of petrochemical plants.

 Analysis of Options:

Option A: General industry publications may lack specificity.

Option B: Past project schedules provide insight but may not reflect the specific context or updated methodologies.

Option C: The handbook is most relevant as it is tailored to the specific project type.

Option D: Cost estimates are useful for budget alignment but not as precise for duration calculation.

 PSP Study Guide References:

The guide advises leveraging validated industry resources for project-specific accuracy in duration estimation​.

 Conclusion: The correct answer is C, as a specialized industry handbook provides the most reliable and context-specific data for duration estimation.