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?
0.86, indicating that the project is over budget and not cost-efficient
1.0, indicating that the project is right on budget
0.75, indicating that the project has a favorable cost variance
1.2, indicating that the project is under budget and cost-efficient