What was the exact constitutional status of India on 26th January, 1950? ​

The answer is B. On 26 January 1950 the Constitution came into force with a Preamble describing India as a Sovereign Democratic Republic. The words Socialist and Secular were not in it. They were inserted by the 42nd Constitutional Amendment Act, 1976, which made it Sovereign Socialist Secular Democratic Republic. So option D describes India after 1976, not in 1950.

• A leaves out Sovereign, which was in the original Preamble. Sovereignty means no external authority controls India's internal and external affairs.
• C adds Secular, which was not in the 1950 text. Secularism was read into Articles 25 to 28 and was later affirmed in cases like S.R. Bommai (1994).
• D adds both Socialist and Secular, and both were added in 1976.

Core concept: the Preamble reflects the Constitution's basic philosophy. It is not a source of enforceable power, but the Supreme Court has used it to interpret the Constitution, and amendments to it are subject to the basic structure doctrine from Kesavananda Bharati (1973).

Mains angle: the 1976 insertions show how Preamble wording becomes a political debate, which is useful for GS-2 on polity and constitutional amendments.

Trap: candidates pick D because it looks like the most complete or current description. The question asks about 1950, so check what the text said on that date.