Multiple choice general knowledge What is the Abbreviation used for 3-Tier AC ? 3AC 3TAC 3C 3A Reveal answer Fill a bubble to check yourself D Correct answer Explanation 3-Tier AC (Third AC) is abbreviated as '3A' in Indian Railways. The pattern for AC classes uses the tier number followed by 'A' for AC. Similarly, 2-Tier AC is '2A' and 1st Class AC is '1A'. Option A (3AC) is a common mistake.