During a project status meeting, a project manager determines that the Earned Value (EV) is $300,000, the Actual Cost (AC) is $350,000, and the Planned Value (PV) is $250,000. What is the Cost Performance Index (CPI) for the project, and what does it signify about the project's cost efficiency?
0.75, indicating that the project has a favorable cost variance
0.86, indicating that the project is over budget and not cost-efficient
1.0, indicating that the project is right on budget
1.2, indicating that the project is under budget and cost-efficient