The 'Instrument of Instructions' contained in the Government of India Act 1935 have been incorporated in the Constitution of India in the year 1950 as

The ‘Instrument of Instructions’ of the Government of India Act, 1935 was explicitly equated by Dr. B.R. Ambedkar with what the Constitution of India calls the Directive Principles of State Policy, indicating direct continuity in purpose and nomenclature [1]. These Directive Principles were incorporated into Part IV of the 1950 Constitution as non‑justiciable guidelines for state policy and governance, directing the State to apply social and economic principles while framing laws and policies [2]. Therefore, the correct incorporation of the 1935 “Instrument of Instructions” in the 1950 Constitution is as the Directive Principles of State Policy (Option 2).

Sources

1. [1] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 9: Directive Principles of State Policy > FEATURES OF THE DIRECTIVE PRINCIPLES > p. 108
2. [2] https://www.mea.gov.in/images/pdf1/part4.pdf