The correct answer is option 'D', Karnataka. Karnataka is known as the IT capital of India because it is home to the city of Bengaluru, which is considered the hub of the country's information technology industry. Bengaluru, also known as Bangalore, has emerged as a major IT destination not only in India but also globally.

Here are some reasons why Karnataka is known as the IT capital of India:

1. Bengaluru's IT Industry: Bengaluru has a well-established and vibrant IT industry, hosting numerous multinational companies, tech startups, and research institutions. The city is known for its technological innovation and has a highly skilled workforce. Many global IT giants, such as Infosys, Wipro, and Tata Consultancy Services, have their headquarters or major offices in Bengaluru.

2. Technological Infrastructure: Karnataka, especially Bengaluru, has developed excellent technological infrastructure to support the IT industry. The city has state-of-the-art IT parks and special economic zones (SEZs) that provide advanced facilities and amenities for IT companies. These IT parks offer world-class office spaces, high-speed internet connectivity, and other essential services required by the industry.

3. Educational Institutions: Karnataka is home to some of the top educational institutions in the country, including the Indian Institute of Science (IISc) and the Indian Institute of Technology (IIT) in Bengaluru. These institutions produce a skilled pool of graduates in fields like computer science and engineering, contributing to the growth of the IT industry.

4. Startup Ecosystem: Karnataka, particularly Bengaluru, has a thriving startup ecosystem. The city has a supportive environment for entrepreneurs, with numerous incubation centers, accelerators, and venture capital firms. This has attracted many tech startups to Bengaluru, making it a hotspot for innovation and entrepreneurship in the IT sector.

Conclusion:
Karnataka, with Bengaluru at its helm, has earned the title of the IT capital of India due to its well-developed IT industry, technological infrastructure, presence of top educational institutions, and a flourishing startup ecosystem. The state continues to attract investments and talent, making it a preferred destination for IT companies and professionals.