Introduction:
The National Stock Exchange (NSE) is one of the leading stock exchanges in India. It provides a platform for investors to trade in various financial instruments such as stocks, derivatives, and mutual funds. As of 2023, the state of Maharashtra leads in the number of registered investors in the NSE, with 1.49 crore investors.

Explanation:
Tamil Nadu:
- Tamil Nadu is one of the 28 states in India, located on the southernmost part of the country.
- It is known for its vibrant economy and industrial development.
- While Tamil Nadu has a substantial number of investors in the NSE, it does not have the highest number among the given options.

Uttar Pradesh:
- Uttar Pradesh is the most populous state in India, located in the northern part of the country.
- It has a diverse economy with a mix of agriculture, industries, and services.
- Uttar Pradesh has a significant number of investors in the NSE, but it does not have the highest number among the given options.

Gujarat:
- Gujarat is a state in western India known for its entrepreneurial spirit and vibrant business environment.
- It has a strong industrial base and is home to several large corporations and financial institutions.
- While Gujarat has a substantial number of investors in the NSE, it does not have the highest number among the given options.

Maharashtra:
- Maharashtra is a state in western India and is home to the financial capital of the country, Mumbai.
- Mumbai houses the headquarters of various financial institutions, including the NSE.
- The state has a robust investor base, with a large number of individuals and institutions participating in the stock market.
- Maharashtra leads in the number of investors in the NSE, with 1.49 crore registered investors as of 2023.

Conclusion:
Among the given options, Maharashtra leads in the number of investors in the NSE, with 1.49 crore registered investors in 2023. The state's strong financial ecosystem, spearheaded by Mumbai, contributes to its significant investor base in the NSE.