Correct Answer: 21 September
Subject: 2025
Explanation: <b>Key Fact</b><br>International Peace Day is observed on 21 September.<br><br><b>Additional Info</b><br>Topic: Important Days. The correct option is <b>A</b> — 21 September.<br><br><b>Why the other options are wrong</b><br><b>Option B</b>: 25 September — not the option marked correct for this question.<br><b>Option C</b>: 30 September — not the option marked correct for this question.<br><b>Option D</b>: 15 September — not the option marked correct for this question.<br><br><b>Exam Trick</b><br>Identify the exact concept tested, then eliminate options that contradict the definition, formula, chronology or fact in the question.<br><br><b>Final Answer</b><br>Option A — 21 September.