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.

When detailed estimates are unavailable, historical production rates can provide reliable data for estimating durations based on past projects with similar work.
* Option A (Eichleay formula) is for overhead cost allocation.
* Option C (Time impact analysis) evaluates delay impacts, not durations.
* Option D (Black-Scholes model) is irrelevant in this context.
Historical data usage is a recognized method in project planning and scheduling practices.

Analyze the Data and Logic:
* Activity 9004 ("Valve House Embankment"): This activity has a direct Finish-to-Start (FS) relationship with Activity 10002, with a lag of 7 days.
* Late Start (LS) and Late Finish (LF): In backward pass calculations, the late finish of the successor activity is adjusted for lag and task duration to determine the late start of the predecessor activity.
Formula for Late Finish (LF):
* The Late Finish of Activity 9004 is derived by taking the Late Start (LS) of Activity 10002, subtracting the lag of 7 days, and subtracting 1 day to calculate the exact finish date.
Correct Date Calculation:
* Given the Late Start (LS) of Activity 10002:
* LS.10002 = 11-28-03.
* Apply the formula:LF.9004 = LS.10002 - Lag.7 - 1 day = 11-28-03 - 7 days - 1 day = 11-20-03.
Cross-Verification with Answer Options:
* Option A: Incorrect. Misrepresents the formula.
* Option B: Incorrect. Incorrect application of logic and lag adjustments.
* Option C: Incorrect. Omits the correct lag consideration.
* Option D: Correct. Matches both formula and calculated date.

Interpret the Narrow Band at "Y":
* The narrow band at "Y" is located on a part of the schedule where activities have been delayed or slowed down.
* Such delays typically indicate resource limitations (e.g., insufficient manpower or equipment).
Reasoning:
* No evidence of rework or activity inactivity is explicitly shown in the diagram.
* Resource limitations are common in network diagrams to explain such periods.
Cross-Verification:
* Option B: Incorrect. No evidence of rework exists.
* Option C: Incorrect. Activity inactivity does not fit the context.
* Option D: Incorrect. Sufficient information is provided.
* Option A: Correct. Resource limitation fits the observed diagram behavior.