Explanation:

- Option 1: Public debt

- Public debt is a part of the economic environment.

- It indicates the total amount of money a government owes.

- Can impact interest rates and economic growth.

- Option 2: Lifestyle of people

- This relates to the social or cultural environment.

- Includes habits, values, and consumer behavior.

- Option 3: Technological changes

- Part of the technological environment, not economic.

- Affects innovation and business operations.

- Option 4: Level of education

- Tied to the social environment.

- Influences workforce quality and economic development indirectly.