After independence, which major event led to the formation of a unified Karnataka state?

The correct answer is: A) States Reorganization Act (1956).

The States Reorganization Act was an act of the Parliament of India enacted in 1956. The act was passed with the objective of reorganizing the states of India on a linguistic basis. The act resulted in the formation of 14 new states, including Karnataka.

The other options are incorrect because:

• The Constitution of India was adopted in 1950, but it did not specify the boundaries of the states. The States Reorganization Act was passed six years later to address this issue.
• The India-Pakistan Partition was a major event that took place in 1947, but it did not have a direct impact on the formation of Karnataka.
• The Quit India Movement was a major event that took place in 1942, but it did not have a direct impact on the formation of Karnataka.

In conclusion, the States Reorganization Act (1956) was the major event that led to the formation of a unified Karnataka state.