Explanation:

- Option 1: Capital expenditure

- It's money spent by a government or organization on acquiring or maintaining fixed assets like land, buildings, and equipment.

- It forms a critical part of a capital budget.

- Option 2: Investment Expenditure

- In the context of a capital budget, it refers to spending on assets that will generate future income or profit.

- Often considered synonymous with capital expenditure.

- Option 3: Income budget

- Typically refers to budget related to income and revenues.

- Not a standard part of the capital budget structure.

- Option 4: Budget Expenditure

- A broad term that could include both capital and revenue expenditures.

- Not specific to the capital budget.

Correct Answer: Option 1: Capital expenditure