正解:C
For a long-term project spanning over several years, it's crucial to include projected inflation rates in the budget estimate1. Inflation can significantly impact the cost of resources over time, and not accounting for it can lead to underestimation of the project's overall cost2. Therefore, to provide a realistic and accurate budget estimate, the project manager should consider the impact of inflation on project costs3. This approach will help ensure that the budget is sufficient to cover the project's needs over its entire duration123. References: ProjectManager, Forecast.app, TeamGantt