Step 1: Recall the definition - per capita income (also called average income) is the total income of the country divided by its total population: $$\text{Per capita income} = \frac{\text{Total income of the country}}{\text{Total population of the country}}$$ Step 2: The concept uses INCOME (not wealth) and uses DIVISION (not multiplication), so options (B), (C) and (D) are ruled out. Step 3: Only option (A) involves total income and total population with division, and is therefore the intended/marked answer. Note for learners: the wording of option (A) reverses the order of the terms; the correct relation is income divided by population. Step 4: The World Development Reports use this average income to classify countries - in 2019 countries with per capita income of US$ 49,300 per annum and above were called rich and those with US$ 2,500 or less were called low-income countries.