Impact of Changing Activity E's Duration:

Activity E's new duration = 4 months.

The critical path passes through Activities A → C → D → E → H → I.

Recalculate Project Duration:

Original duration with E = 3 months: 19 months.

Increasing E to 4 months does not impact the overall path since it remains within the critical path's time allowance.

Overall project duration remains 19 months.

Cross-Verification:

Option B: Incorrect. Assumes additional delays.

Option C: Incorrect. Overestimates delays.

Option D: Incorrect. Miscalculates path changes.

Option A: Correct. Matches revised critical path duration.