The correct answer is A) Hyderabad.
Hyderabad is the capital of Telangana and the sixth most populous city in India. It has a population of over 7 million people, making it the most populous district in Telangana. The city is located on the banks of the Musi River and is a major center for business, education, and culture.
Karimnagar is the second most populous district in Telangana, with a population of over 3 million people. The district is located in the northern part of the state and is known for its agricultural production.
Warangal is the third most populous district in Telangana, with a population of over 2 million people. The district is located in the central part of the state and is known for its historical monuments.
Rangareddy is the fourth most populous district in Telangana, with a population of over 1 million people. The district is located in the southern part of the state and is a major center for IT and manufacturing.
In conclusion, Hyderabad is the district in Telangana with the highest population density. The city is a major center for business, education, and culture.