The labour law reforms bundled several older statutes into four new codes, and the Industrial Relations Code specifically targeted the laws governing the employer-employee relationship, not industrial licensing.
Because the Code's scope is industrial relations specifically, the licensing-and-regulation statute sits outside its consolidation.
\[ \boxed{\text{Industries (Development and Regulation) Act, 1951 (IDR Act)}} \]Grouping the four Acts by subject matter, rather than trying to recall the Code's contents from memory alone, makes the odd one out easy to spot.
Three Acts cluster around labour relations, while the fourth belongs to a different regulatory family entirely, industrial licensing, making it the one not part of the Code.
Hence, the correct answer is Industries (Development and Regulation) Act, 1951 (IDR Act).