If the project's performance is expressed by this graph, which of the following could be a possible explanation of the project's performance?

a. The project is performing ahead of schedule and under budget

b. The project team are working on the project tasks but are making mistakes which require rework before each task can be considered complete

c. The project team are not spending as much time as expected on this project so the tasks are not being completed as scheduled

e. The estimates used in the project plan were inflated