Himachal Pradesh first came into existence as a centrally administered territory on

The correct answer is: B. 28th December, 1956

Himachal Pradesh first came into existence as a centrally administered territory on 28th December, 1956. It was formed by merging the former princely states of Bilaspur, Chamba, Kangra, Kullu, Lahaul and Spiti, Mandi, Sirmaur, and Shimla.

The other options are incorrect because:

• Option A is the date of India’s independence from British rule.
• Option C is the date on which the Indian Constitution came into effect.
• Option D is the date on which India became a republic.