Which of the following would be included in calculation of national income?1. Commission paid to a salesman2. Subsidies paid to a farmer3. Social Security payments4. Payments to a part time polytechnic lecturerSelect the correct answer using codes given below:

National income accounting is a government bookkeeping system that measures a country's economic activity - offering insight into how an economy is performing. Such a system will include total revenues by domestic corporations, wages paid, and sales and income tax data for companies.