If someone wanted to constrain a project's end date so that any project slippage would...

To constrain a project's end date, a Finish-No-Later constraint is applied to the last activity. This ensures any slippage results in negative float, signaling delays relative to the fixed deadline.

Option A and B apply to earlier constraints, which are not relevant for controlling the project's end date.

Option D applies a constraint to the first activity, not the project finish.

This concept aligns with controlling project deadlines as described in the PSP Study Guide​.