The state of Kerala was formed in 1956 based on:

Administrative convenience
Linguistic unity
Religious majority
Historical kingdoms

The correct answer is: B) Linguistic unity.

Kerala was formed on 1 November 1956 as a result of the States Reorganisation Act, 1956. The Act was passed by the Parliament of India to reorganize the states of India on a linguistic basis. The formation of Kerala was based on the principle of linguistic unity, as the state was formed by merging the Malayalam-speaking regions of the erstwhile Madras Presidency, Travancore-Cochin State, and Malabar District of the princely state of Cochin.

The other options are incorrect because:

  • Option A: Administrative convenience is not the reason for the formation of Kerala. The state was not formed to make it easier for the government to administer the region.
  • Option C: Religious majority is not the reason for the formation of Kerala. The state was not formed to create a state with a Hindu majority.
  • Option D: Historical kingdoms is not the reason for the formation of Kerala. The state was not formed to create a state that corresponded to the boundaries of historical kingdoms.