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

What was the exact constitutional status of India on 26th January, 1950?
(a) A democratic Republic
(b) A Sovereign Democratic Republic
(c) A Sovereign Secular Democratic Republic
(d) A Sovereign Socialist Secular Democratic Republic

Answer – (b) A Sovereign Democratic Republic

Socialist and Secular are the words added in 42th Constitutional amendment of 1976.