Explanation:

- Consumption (Option 1): This refers to the use of goods and services by households. It’s considered an outflow in the circular flow of income, as money is being spent.

- Investment (Option 2): This is the spending on capital goods like machinery and buildings. Investment is an inflow as it adds money to the economic cycle.

- Income (Option 3): This is the money earned by individuals, usually as wages or profits. For households, income is an inflow, but in the context of overall flow, it can be both inflow and outflow.

- All of these (Option 4): Not all listed are inflows (consumption is an outflow).

Correct Answer:

Option 2: Investment is included as an inflow.