Karnataka’s population rank among Indian states (as per Census 2011):

The correct answer is A) 5th.

Karnataka is the 5th most populous state in India, with a population of 61,130,704 as per the 2011 census. It is located in the southern part of the country and has a land area of 191,791 square kilometers. The capital of Karnataka is Bangalore, which is also the third most populous city in India.

The other options are incorrect because:

• Option B) 8th is the population rank of Maharashtra.
• Option C) 10th is the population rank of Tamil Nadu.
• Option D) 12th is the population rank of West Bengal.