According to the PMBOK® Guide, specifically within the Earned Value Management (EVM) framework used in the Control Costs and Control Schedule processes, the Schedule Variance (SV) is a measure of schedule performance expressed as the difference between the earned value and the planned value.

The Formula:

$$SV = EV - PV$$

Behavior at Project Completion:

Planned Value (PV): This is the authorized budget assigned to scheduled work. At the end of the project, all work is scheduled to be finished, so the $PV$ equals the Budget at Completion (BAC).

Earned Value (EV): This is the measure of work actually performed. At the end of the project, all work has been completed, so the $EV$ also equals the Budget at Completion (BAC).

The Result: Because both $EV$ and $PV$ equal the total budget ($BAC$) when the project is finished, the calculation becomes $BAC - BAC = 0$.

Analysis of Other Options:

A. Positive: A positive $SV$ during the project indicates that the project is ahead of schedule. However, once the project is closed, the " ahead " status is reconciled because no more work is planned.

C. Negative: A negative $SV$ during the project indicates that the project is behind schedule. Similar to a positive $SV$, this value resets to zero once all planned work is eventually completed.

D. Greater than one: This describes a Schedule Performance Index (SPI) ($EV / PV$), not the Schedule Variance ($SV$). While an $SPI$ of 1.0 is achieved at the end of a project, $SV$ is a numerical value (currency or hours), not a ratio.