Correct Answer: (a) It is the money value of all the goods and services produced in a country in a year.
Solution:National income is the money value of all final goods and services produced in a country in a year. It also includes net income earned from abroad. According to Marshall, "The labor and capital of a country together with the natural resources of that country produces some physical and non-material goods every year, including services. The market value of this is called national income'.