Expenditure on Construction of Metro:
This expenditure would be classified as capital expenditure. Here's why:

- Long-term benefit: Construction of metro involves the creation of a permanent asset that provides long-term benefits to the society. The metro infrastructure, once built, can be used for several years, and hence it is considered a capital expenditure.

- Enhanced productivity: Metro systems help in reducing traffic congestion, improving transportation efficiency, and promoting economic growth. These long-term benefits contribute to the enhancement of productivity in the region.

- Investment in infrastructure: The construction of metro requires significant investment in infrastructure, including stations, tracks, trains, and other related facilities. These assets have a substantial lifespan and contribute to the development and expansion of urban infrastructure.

- Income generation: Metro systems can generate revenue through ticket sales, advertising, and other sources. Although the revenue may not cover the entire construction cost, it still contributes to the financial sustainability of the project.

Grants Given by Central Government to State Government:
The grants given by the central government to the state government would be classified as revenue expenditure. Here's why:

- Short-term benefit: Grants provided by the central government to the state government are typically intended to meet the immediate financial needs of the states. These grants are used for various purposes such as funding welfare schemes, infrastructure development, and social programs.

- Operational expenses: State governments utilize these grants for meeting their day-to-day operational expenses, including salaries, maintenance costs, and other routine expenditures. These expenses do not result in the creation of permanent assets or long-term benefits.

- Non-capital nature: Revenue expenditure is characterized by its non-capital nature, as it is incurred for the ongoing operations and maintenance of existing assets. Grants provided by the central government fall under this category, as they do not lead to the creation of new capital assets.

Repayment of Loan Taken from World Bank:
The repayment of a loan taken from the World Bank would be classified as revenue expenditure. Here's why:

- Loan repayment: Repayment of a loan is considered a revenue expenditure because it involves the outflow of funds from the government's revenue to fulfill its contractual obligation to repay the borrowed amount.

- No creation of assets: Loan repayments do not result in the creation of new capital assets. Instead, they are used to fulfill the financial obligations incurred in the past for various purposes such as infrastructure development, social programs, or other governmental expenses.

- Interest component: Loan repayments typically include both the principal amount borrowed and the interest charged on the loan. The interest component represents the cost of borrowing and is treated as a revenue expenditure.

- Non-capital nature: Revenue expenditure refers to the expenses incurred for the day-to-day operations and maintenance of existing assets. Loan repayment falls under this category as it does not lead to the creation of new capital assets but involves the fulfillment of financial obligations.