A key economic reform undertaken by Tamil Nadu focused on improving:

Infrastructure
Fiscal Consolidation
Foreign Direct Investment
Subsidy Regimes

The correct answer is: Infrastructure.

Tamil Nadu has undertaken a number of economic reforms in recent years, with a focus on improving infrastructure. The state has invested heavily in roads, bridges, ports, airports, and other infrastructure projects. This has helped to improve the state’s competitiveness and attract investment.

Fiscal consolidation is the process of reducing a government’s budget deficit. This can be done by raising taxes, cutting spending, or both. Tamil Nadu has made some progress in fiscal consolidation in recent years, but the state still has a large budget deficit.

Foreign direct investment (FDI) is the investment of money by foreign companies in a country’s economy. Tamil Nadu has been successful in attracting FDI in recent years. The state has a number of advantages for foreign investors, including a skilled workforce, a good infrastructure, and a stable political environment.

Subsidy regimes are government programs that provide financial assistance to individuals or businesses. Tamil Nadu has a number of subsidy programs, including programs to support farmers, small businesses, and the poor. These programs can help to reduce poverty and inequality, but they can also be costly and inefficient.

In conclusion, the key economic reform undertaken by Tamil Nadu focused on improving infrastructure. This has helped to improve the state’s competitiveness and attract investment.