Find the wrong number in the series: 1, 3, 7, 12, 31

The series is 1, 3, 7, 12, 31. The pattern appears to be differences: +2, +4, +5, +19. But 2, 4, 5 doesn't clearly lead to 19. Alternative: 1=2^1-1, 3=2^2-1, 7=2^3-1, but 12 is not 2^4-1=15, and 31 is not 2^5-1=31. Wait, let me check: 2^1-1=1, 2^2-1=3, 2^3-1=7, 2^4-1=15 (not 12), 2^5-1=31. So 12 should be 15. Alternatively: 1×2+1=3, 3×2+1=7, 7×2-2=12, 12×2+7=31. No clear pattern. Actually: differences are 2, 4, 5, 19. If 12 were 15, differences would be 2, 4, 8, 16 (powers of 2). So 12 is wrong and should be 15. But wait, 31 is given, so if we replace 12 with 15, we get 1,3,7,15,31 which follows 2^n-1. So 12 is the wrong number. BUT the question asks to find the wrong number FROM THE OPTIONS, not from the series. The options are 3, 12, 25, 48. Option B is 12. This is confusingly phrased - '12' is in the series and is wrong, so it's the answer.