National income accounting is a. an accounting system used by businesses to calculate their profits during a given production period. b. used by international organizations such as the world bank to determine individual country assessments (fees). c. a system used by tax accountants to calculate the tax liabilities of transnational corporations. d. a system of accounts designed to measure aggregate economic activity in a country.

The answer is "a system of accounts designed to measure aggregate economic activity in a country".

National income accounting is an accounting framework that a government uses to gauge the level of the nation's financial movement in a given day and age. Accounting records of this nature incorporate information with respect to total incomes earned by domestic partnerships, salary paid to outside and local laborers, and the sum spent on sales and income taxes by enterprises and people living in the nation.